WorldWideScience

Sample records for burrowing denning dinosaur

  1. Dinosaur Day!

    Science.gov (United States)

    Nakamura, Sandra; Baptiste, H. Prentice

    2006-01-01

    In this article, the authors describe how they capitalized on their first-grade students' love of dinosaurs by hosting a fun-filled Dinosaur Day in their classroom. On Dinosaur Day, students rotated through four dinosaur-related learning stations that integrated science content with art, language arts, math, and history in a fun and time-efficient…

  2. Dinosaur tectonics

    DEFF Research Database (Denmark)

    Graversen, Ole; Milàn, Jesper; B. Loope, David

    2007-01-01

    A dinosaur trackway in the Middle Jurassic eolian Entrada Sandstone of southern Utah, USA, exposes three undertracks that we have modeled as isolated tectonic regimes showing the development of fold-thrust ramp systems induced by the dinosaur's feet. The faulted and folded sequence is comparable...... to crustal scale tectonics associated with plate tectonics and foreland fold-thrust belts. A structural analysis of the dinosaur tracks shows the timing and direction of the forces exercised on the substrate by the animal's foot during the stride. Based on the structural analysis, we establish a scenario...... the back. As the body accelerated, the foot was forced backward. The rotated disc was forced backward along a detachment fault that was bounded by lateral ramps. The interramp segment matches the width of the dinosaur's foot which created an imbricate fan thrust system that extended to the far end...

  3. Dinosaur lactation?

    Science.gov (United States)

    Else, Paul L

    2013-02-01

    Lactation is a process associated with mammals, yet a number of birds feed their newly hatched young on secretions analogous to the milk of mammals. These secretions are produced from various sections (crop organ, oesophageal lining and proventriculus) of the upper digestive tract and possess similar levels of fat and protein, as well as added carotenoids, antibodies and, in the case of pigeons and doves, epidermal growth factor. Parental care in avian species has been proposed to originate from dinosaurs. This study examines the possibility that some dinosaurs used secretory feeding to increase the rate of growth of their young, estimated to be similar to that of present day birds and mammals. Dinosaur 'lactation' could also have facilitated immune responses as well as extending parental protection as a result of feeding newly hatched young in nest environments. While the arguments for dinosaur lactation are somewhat generic, a case study for lactation in herbivorous site-nesting dinosaurs is presented. It is proposes that secretory feeding could have been used to bridge the gap between hatching and establishment of the normal diet in some dinosaurs.

  4. Dinosaur biomechanics

    OpenAIRE

    Alexander, R. McNeill

    2006-01-01

    Biomechanics has made large contributions to dinosaur biology. It has enabled us to estimate both the speeds at which dinosaurs generally moved and the maximum speeds of which they may have been capable. It has told us about the range of postures they could have adopted, for locomotion and for feeding, and about the problems of blood circulation in sauropods with very long necks. It has made it possible to calculate the bite forces of predators such as Tyrannosaurus, and the stresses they imp...

  5. Dinosaur Dioramas.

    Science.gov (United States)

    Scheinkman, Nancy

    2001-01-01

    Describes an art project for second-grade students where in over five class periods, they create fired clay dinosaur sculptures with dioramas as the background. States that this project, the culminating activity for a sculpture unit, teaches students many art terms and uses of different media. (CMK)

  6. Recycling of Badger/Fox Burrows in Late Pleistocene Loess by Hyenas at the Den Site Bad Wildungen-Biedensteg (NW, Germany: Woolly Rhinoceros Killers and Scavengers in a Mammoth Steppe Environment of Europe

    Directory of Open Access Journals (Sweden)

    Cajus Diedrich

    2013-01-01

    Full Text Available The Late Pleistocene (MIS 5c-d Ice Age spotted hyena open air den and bone accumulation site Bad Wildungen-Biedensteg (Hesse, NW, Germany represents the first open air loess fox/badger den site in Europe, which must have been recycled by Crocuta crocuta spelaea (Goldfuss, 1823 as a birthing den. Badger and fox remains, plus remains of their prey (mainly hare, have been found within the loess. Hyena remains from that site include parts of cub skeletons which represent 10% of the megafauna bones. Also a commuting den area existed, which was well marked by hyena faecal pellets. Most of the hyena prey bones expose crack, bite, and nibbling marks, especially the most common bones, the woolly rhinoceros Coelodonta antiquitatis (NISP  =  32%. The large amount of woolly rhinoceros bones indicate hunting/scavenging specializing on this large prey by hyenas. Other important mammoth steppe hyena prey remains are from Mammuthus primigenius, Equus caballus przewalskii, Bison/Bos, Megaloceros giganteus, Cervus elaphus, and Rangifer tarandus. The few damaged bone remains of a scavenged cave bear Ursus spelaeus subsp. are unique for an open air situation. Abundant micromammal, frog, and some fish remains were concentrated in “pellets” that contain mainly mammoth steppe micromammals and also frog and fish remains that seem to originate from the nearby river/lake.

  7. Dinosaur biomechanics.

    Science.gov (United States)

    Alexander, R McNeill

    2006-08-07

    Biomechanics has made large contributions to dinosaur biology. It has enabled us to estimate both the speeds at which dinosaurs generally moved and the maximum speeds of which they may have been capable. It has told us about the range of postures they could have adopted, for locomotion and for feeding, and about the problems of blood circulation in sauropods with very long necks. It has made it possible to calculate the bite forces of predators such as Tyrannosaurus, and the stresses they imposed on its skull; and to work out the remarkable chewing mechanism of hadrosaurs. It has shown us how some dinosaurs may have produced sounds. It has enabled us to estimate the effectiveness of weapons such as the tail spines of Stegosaurus. In recent years, techniques such as computational tomography and finite element analysis, and advances in computer modelling, have brought new opportunities. Biomechanists should, however, be especially cautious in their work on animals known only as fossils. The lack of living specimens and even soft tissues oblige us to make many assumptions. It is important to be aware of the often wide ranges of uncertainty that result.

  8. Brushing up on Dinosaurs.

    Science.gov (United States)

    Weisburd, Stefi

    1986-01-01

    Describes new methods of reconstruction of dinosaurs using skeletons, mummified skin, and muscle scars, along with clay and paint. Examines some inaccuracies in dinosaur's physical characteristics and behaviors suggested by recent findings. (TW)

  9. What's New, Dinosaur?

    Science.gov (United States)

    Prime, Carol Spirkoff; Cox, Judy

    1987-01-01

    Activities and information relating to dinosaurs are presented, including: study of warm- and cold-blooded animals; research about recent dinosaur discoveries; track-making; studying and making fossils; and extinction theories. (CB)

  10. Dinosaur Extinction, Early Childhood Style

    Science.gov (United States)

    Murray, Mary; Valentine-Anand, Lesley

    2008-01-01

    Do dinosaurs have bellybuttons? This intriguing question launched a journey into inquiry science that captivated a class of four-year-olds for eight months. As students enjoyed dinosaur books, examined dinosaur artifacts, drew pictures, watched videos, and generally immersed themselves in all things dinosaur, the authors built a culture of…

  11. Paleobiology of Herbivorous Dinosaurs

    Science.gov (United States)

    Barrett, Paul M.

    2014-05-01

    Herbivorous dinosaurs were abundant, species-rich components of Late Triassic-Cretaceous terrestrial ecosystems. Obligate high-fiber herbivory evolved independently on several occasions within Dinosauria, through the intermediary step of omnivory. Anatomical character complexes associated with this diet exhibit high levels of convergence and morphological disparity, and may have evolved by correlated progression. Dinosaur faunas changed markedly during the Mesozoic, from early faunas dominated by taxa with simple, uniform feeding mechanics to Cretaceous biomes including diverse sophisticated sympatric herbivores; the environmental and biological drivers causing these changes remain unclear. Isotopic, taphonomic, and anatomical evidence implies that niche partitioning reduced competition between sympatric herbivores, via morphological differentiation, dietary preferences, and habitat selection. Large body size in dinosaur herbivores is associated with low plant productivity, and gave these animals prominent roles as ecosystem engineers. Although dinosaur herbivores lived through several major events in floral evolution, there is currently no evidence for plant-dinosaur coevolutionary interactions.

  12. Dinosaur physiology. Evidence for mesothermy in dinosaurs.

    Science.gov (United States)

    Grady, John M; Enquist, Brian J; Dettweiler-Robinson, Eva; Wright, Natalie A; Smith, Felisa A

    2014-06-13

    Were dinosaurs ectotherms or fast-metabolizing endotherms whose activities were unconstrained by temperature? To date, some of the strongest evidence for endothermy comes from the rapid growth rates derived from the analysis of fossil bones. However, these studies are constrained by a lack of comparative data and an appropriate energetic framework. Here we compile data on ontogenetic growth for extant and fossil vertebrates, including all major dinosaur clades. Using a metabolic scaling approach, we find that growth and metabolic rates follow theoretical predictions across clades, although some groups deviate. Moreover, when the effects of size and temperature are considered, dinosaur metabolic rates were intermediate to those of endotherms and ectotherms and closest to those of extant mesotherms. Our results suggest that the modern dichotomy of endothermic versus ectothermic is overly simplistic.

  13. Burrowing owl survey : 1994 report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Report of burrowing owl nesting activity in the Central Region of Colorado in 1994, produced by the Colorado Division of Wildlife. There is little long term data on...

  14. Depth of artificial Burrowing Owl burrows affects thermal suitability and occupancy

    Science.gov (United States)

    Nadeau, Christopher P.; Conway, Courtney J.; Rathbun, Nathan

    2015-01-01

    Many organizations have installed artificial burrows to help bolster local Burrowing Owl (Athene cunicularia) populations. However, occupancy probability and reproductive success in artificial burrows varies within and among burrow installations. We evaluated the possibility that depth below ground might explain differences in occupancy probability and reproductive success by affecting the temperature of artificial burrows. We measured burrow temperatures from March to July 2010 in 27 artificial burrows in southern California that were buried 15–76 cm below the surface (measured between the surface and the top of the burrow chamber). Burrow depth was one of several characteristics that affected burrow temperature. Burrow temperature decreased by 0.03°C per cm of soil on top of the burrow. The percentage of time that artificial burrows provided a thermal refuge from above-ground temperature decreased with burrow depth and ranged between 50% and 58% among burrows. The percentage of time that burrow temperature was optimal for incubating females also decreased with burrow depth and ranged between 27% and 100% among burrows. However, the percentage of time that burrow temperature was optimal for unattended eggs increased with burrow depth and ranged between 11% and 95% among burrows. We found no effect of burrow depth on reproductive success across 21 nesting attempts. However, occupancy probability had a non-linear relationship with burrow depth. The shallowest burrows (15 cm) had a moderate probability of being occupied (0.46), burrows between 28 and 40 cm had the highest probability of being occupied (>0.80), and burrows >53 cm had the lowest probability of being occupied (Owls may prefer burrows at moderate depths because these burrows provide a thermal refuge from above-ground temperatures, and are often cool enough to allow females to leave eggs unattended before the onset of full-time incubation, but not too cool for incubating females that spend most of

  15. On Dinosaur Growth

    Science.gov (United States)

    Erickson, Gregory M.

    2014-05-01

    Despite nearly two centuries of investigation, a comprehensive understanding of dinosaur biology has proven intractable. The recent development of means to study tissue-level growth, age these animals, and make growth curves has revolutionized our knowledge of dinosaur lives. From such data it is now understood that dinosaurs grew both disruptively and determinately; that they rarely if ever exceeded a century in age; that they became giants through accelerated growth and dwarfed through truncated development; that they were likely endothermic, sexually matured like crocodiles, and showed survivorship like populations of large mammals; and that basal birds retained dinosaurian physiology.

  16. The dinosaurs of Thailand

    Science.gov (United States)

    Buffetaut, Eric; Suteethorn, Varavudh

    After more than ten years of Thai-French research, the Thai dinosaur record, from the continental rocks of the Khorat Plateau, is, to date, the best in Southeast Asia. The oldest evidence consists of footprints of small dinosaurs from the Middle to Late Jurassic Phra Wihan Formation. The most varied dinosaur assemblage hitherto found in Thailand comes from the Late Jurassic Sao Khua Formation; it is dominated by sauropods, but also includes various theropods. Large theropod footprints are known from the Early Cretaceous Phu Phan Formation. Theropods and the primitive ceratopsian Psittacosaurus occur in the Aptian-Albian Khok Kruat Formation.

  17. Warm and Cool Dinosaurs.

    Science.gov (United States)

    Mannlein, Sally

    2001-01-01

    Presents an art activity in which first grade students draw dinosaurs in order to learn about the concept of warm and cool colors. Explains how the activity also helped the students learn about the concept of distance when drawing. (CMK)

  18. Dinosaur Reproduction and Parenting

    Science.gov (United States)

    Horner, John R.

    Non-avian dinosaur reproductive and parenting behaviors were mostly similar to those of extant archosaurs. Non-avian dinosaurs were probably sexually dimorphic and some may have engaged in hierarchical rituals. Non-avian coelurosaurs (e.g. Troodontidae, Oviraptorosauria) had two active oviducts, each of which produced single eggs on a daily or greater time scale. The eggs of non-coelurosaurian dinosaurs (e.g. Ornithischia, Sauropoda) were incubated in soils, whereas the eggs of non-avian coelurosaurs (e.g. Troodon, Oviraptor) were incubated with a combination of soil and direct parental contact. Parental attention to the young was variable, ranging from protection from predators to possible parental feeding of nest-bound hatchlings. Semi-altricial hadrosaur hatchlings exited their respective nests near the time of their first linear doubling. Some reproductive behaviors, once thought exclusive to Aves, arose first in non-avian dinosaurs. The success of the Dinosauria may be related to reproductive strategies.

  19. Dinosaur Eggs and Babies

    Science.gov (United States)

    Carpenter, Kenneth; Hirsch, Karl F.; Horner, John R.

    1996-01-01

    In the last couple of decades the study of dinosaur eggs and babies has proved to be one of the most exciting and profitable areas of dinosaur research. This is the first book solely devoted to this topic and reviews, in scientific detail, our present state of knowledge about this exciting area of palaeontology. Chapters in the book discuss all aspects of the science including the occurrence of eggs, nests and baby skeletons, descriptive osteology of juvenile skeletons, comparative histology of juvenile bone, analyses of eggs and egg shells, palaeoenvironments of nesting sites, nesting behaviour and developmental growth of baby dinosaurs. The volume will be an invaluable addition to the book collections of vertebrate palaeontologists and their graduate students.

  20. Archaeopteryx: Dinosaur or Bird?

    Institute of Scientific and Technical Information of China (English)

    SONG Jianlan

    2011-01-01

    @@ An Archaeopteryx-like theropod dinosaur newly found from western Liaoning Province in northeastern China would make an unusual, if not unwelcome, gift for the 150th birthday of Archaeopteryx, the oldest bird as long-believed by paleontologists: Named as Xiaotingia zhengiis, the new species carries some critical traits suggesting that Archaeopteryx might have actually been a dinosaur.Naturally this breaking news stirred intense controversies.Was "The Oldest Bird" a bird? If not, what makes a bird? With these questions in mind, the author joined an exploration in search of "the real first bird" along with the paleontologists at the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) under CAS.

  1. A Child Centered Approach to Dinosaurs.

    Science.gov (United States)

    Strader, William H.; Rinker, Catherine A.

    1989-01-01

    Describes a curriculum for teaching young children about dinosaurs. Activity topics included Diplodocus eggs, sorting dinosaurs, creating terrariums, and extinction. Describes the incorporation of dinosaur activities into other subject areas and resource materials. (RJC)

  2. Kindergartners Love Dinosaurs

    Science.gov (United States)

    Stollon, Marcy

    2005-01-01

    In this article, the author relates how she uses an art lesson that integrates art, language arts, and science in an enjoyable, creative project about dinosaurs in her kindergarten class. She relates how the children enjoy being illustrators and becoming familiar with well-known children's illustrators. She also relates that she starts her classes…

  3. Giant Dinosaur Find

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Fossil site could provide answers to mystery of extinction Chinese scientists claim to have discovered the world’s largest dinosaur fossil site in eastern Shandong Province, which is expected to shed light on the animal’s mysterious extinction toward the end of the Cretaceous Period 65 millionyears ago.

  4. Dinosaurs' True Colors

    Institute of Scientific and Technical Information of China (English)

    TANG YUANKAI

    2010-01-01

    @@ On March 10,the Beijing Museum of Natural History(BMNH)announced scientists from China and abroad had decoded the full-body color patterns of a dinosaur,a small theropod named as anchiomis huxleyi,for the first time.

  5. Evolution of dinosaur epidermal structures.

    Science.gov (United States)

    Barrett, Paul M; Evans, David C; Campione, Nicolás E

    2015-06-01

    Spectacularly preserved non-avian dinosaurs with integumentary filaments/feathers have revolutionized dinosaur studies and fostered the suggestion that the dinosaur common ancestor possessed complex integumentary structures homologous to feathers. This hypothesis has major implications for interpreting dinosaur biology, but has not been tested rigorously. Using a comprehensive database of dinosaur skin traces, we apply maximum-likelihood methods to reconstruct the phylogenetic distribution of epidermal structures and interpret their evolutionary history. Most of these analyses find no compelling evidence for the appearance of protofeathers in the dinosaur common ancestor and scales are usually recovered as the plesiomorphic state, but results are sensitive to the outgroup condition in pterosaurs. Rare occurrences of ornithischian filamentous integument might represent independent acquisitions of novel epidermal structures that are not homologous with theropod feathers.

  6. The first Brazilian Dinosaur Symposium

    Science.gov (United States)

    dos Anjos Candeiro, Carlos Roberto; da Silva Marinho, Thiago

    2015-08-01

    The 1st Brazilian Dinosaur Symposium gathered paleontologists, geologists, and paleoartists in the city of Ituiutaba, Minas Gerais State, Brazil, from April 21st to 24th, 2013. The Dinosaur Symposium in the Pontal Campus of the Universidade Federal de Uberlândia, Minas Gerais State, Brazil provided an opportunity to share many new results of dinosaur research being conducted around the world. The symposium coincided with a new dawn of scientific advances in dinosaur paleontology further expanding its importance, interest and credibility worldwide.

  7. Dinosaur fossils predict body temperatures.

    Directory of Open Access Journals (Sweden)

    James F Gillooly

    2006-07-01

    Full Text Available Perhaps the greatest mystery surrounding dinosaurs concerns whether they were endotherms, ectotherms, or some unique intermediate form. Here we present a model that yields estimates of dinosaur body temperature based on ontogenetic growth trajectories obtained from fossil bones. The model predicts that dinosaur body temperatures increased with body mass from approximately 25 degrees C at 12 kg to approximately 41 degrees C at 13,000 kg. The model also successfully predicts observed increases in body temperature with body mass for extant crocodiles. These results provide direct evidence that dinosaurs were reptiles that exhibited inertial homeothermy.

  8. Den gode argumentations anatomi

    DEFF Research Database (Denmark)

    Kock, Christian Erik J

    2013-01-01

    God argumentation har tre dimensioner: Den er faktuelt retvisende, den er relevant, og den er vægtig. Desværre slipper politikerne ofte af sted med mangelfuld argumentation fordi de forklæder den godt. Derfor får du her de vigtigste redskaber til at spotte uskikkene i politisk argumentation...

  9. Den unge Heidegger

    DEFF Research Database (Denmark)

    Den første antologi på dansk om den unge Heideggers skrifter og udviklingen før Væren og tid......Den første antologi på dansk om den unge Heideggers skrifter og udviklingen før Væren og tid...

  10. Den performative by

    DEFF Research Database (Denmark)

    Samson, Kristine

    2012-01-01

    Den performative by omhandler den æstetiske og affektive drejning, der finder sted inden for kulturel byudvikling i øjeblikket......Den performative by omhandler den æstetiske og affektive drejning, der finder sted inden for kulturel byudvikling i øjeblikket...

  11. Making Sense of Dinosaur Tracks

    Science.gov (United States)

    MacKenzie, Ann Haley; McDowell, Brian

    2012-01-01

    What do paleontologists, dinosaur tracks, and the nature of science have in common? They're combined here in an inquiry activity where students use methods of observation and inference to devise evidence-based explanations for the data they collect about dinosaur tracks, much like the methods used by paleontologists. Students then debate the…

  12. A dark day for dinosaurs

    Science.gov (United States)

    Edwards, Pete

    2015-11-01

    On average, 91 people are killed by asteroids each year. In her book Dark Matter and the Dinosaurs, theoretical physicist Lisa Randall focuses on a novel question: how did a dinosaur-killing asteroid end up on its collision course with Earth in the first place?

  13. If You Were a Dinosaur...

    Science.gov (United States)

    Ashbrook, Peggy

    2010-01-01

    Dinosaurs are one of those science topics that draw children in and teach them about concepts like measuring and using descriptive language. Learning about dinosaurs, although not hands-on like observing and recording caterpillar growth, develops critical thinking and introduces animal diversity and the relations between body form and function.…

  14. Dinosaur footprints and other ichnofauna from the cretaceous Kem Kem beds of Morocco.

    Directory of Open Access Journals (Sweden)

    Nizar Ibrahim

    Full Text Available We describe an extensive ichnofossil assemblage from the likely Cenomanian-age 'lower' and 'upper' units of the 'Kem Kem beds' in southeastern Morocco. In the lower unit, trace fossils include narrow vertical burrows in cross-bedded sandstones and borings in dinosaur bone, with the latter identified as the insect ichnotaxon Cubiculum ornatus. In the upper unit, several horizons preserve abundant footprints from theropod dinosaurs. Sauropod and ornithischian footprints are much rarer, similar to the record for fossil bone and teeth in the Kem Kem assemblage. The upper unit also preserves a variety of invertebrate traces including Conichnus (the resting trace of a sea-anemone, Scolicia (a gastropod trace, Beaconites (a probable annelid burrow, and subvertical burrows likely created by crabs for residence and detrital feeding on a tidal flat. The ichnofossil assemblage from the Upper Cretaceous Kem Kem beds contributes evidence for a transition from predominantly terrestrial to marine deposition. Body fossil and ichnofossil records together provide a detailed view of faunal diversity and local conditions within a fluvial and deltaic depositional setting on the northwestern coast of Africa toward the end of the Cretaceous.

  15. Dinosaur footprints and other ichnofauna from the cretaceous Kem Kem beds of Morocco.

    Science.gov (United States)

    Ibrahim, Nizar; Varricchio, David J; Sereno, Paul C; Wilson, Jeffery A; Wilson, Jeff A; Dutheil, Didier B; Martill, David M; Baidder, Lahssen; Zouhri, Samir

    2014-01-01

    We describe an extensive ichnofossil assemblage from the likely Cenomanian-age 'lower' and 'upper' units of the 'Kem Kem beds' in southeastern Morocco. In the lower unit, trace fossils include narrow vertical burrows in cross-bedded sandstones and borings in dinosaur bone, with the latter identified as the insect ichnotaxon Cubiculum ornatus. In the upper unit, several horizons preserve abundant footprints from theropod dinosaurs. Sauropod and ornithischian footprints are much rarer, similar to the record for fossil bone and teeth in the Kem Kem assemblage. The upper unit also preserves a variety of invertebrate traces including Conichnus (the resting trace of a sea-anemone), Scolicia (a gastropod trace), Beaconites (a probable annelid burrow), and subvertical burrows likely created by crabs for residence and detrital feeding on a tidal flat. The ichnofossil assemblage from the Upper Cretaceous Kem Kem beds contributes evidence for a transition from predominantly terrestrial to marine deposition. Body fossil and ichnofossil records together provide a detailed view of faunal diversity and local conditions within a fluvial and deltaic depositional setting on the northwestern coast of Africa toward the end of the Cretaceous.

  16. Idealismen og dens kritikere

    DEFF Research Database (Denmark)

    Huggler, Jørgen

    2006-01-01

    En idéhistorisk redegørelse for filosofien i tiden mellem 1789 og 1857 - med hovedvægt på kritikken af den franske revolution, den tyske idealisme (Fichte, Schelling, Hegel) samt positivismen i Frankrig.......En idéhistorisk redegørelse for filosofien i tiden mellem 1789 og 1857 - med hovedvægt på kritikken af den franske revolution, den tyske idealisme (Fichte, Schelling, Hegel) samt positivismen i Frankrig....

  17. The biomechanics of burrowing and boring.

    Science.gov (United States)

    Dorgan, Kelly M

    2015-01-15

    Burrowers and borers are ecosystem engineers that alter their physical environments through bioturbation, bioirrigation and bioerosion. The mechanisms of moving through solid substrata by burrowing or boring depend on the mechanical properties of the medium and the size and morphology of the organism. For burrowing animals, mud differs mechanically from sand; in mud, sediment grains are suspended in an organic matrix that fails by fracture. Macrofauna extend burrows through this elastic mud by fracture. Sand is granular and non-cohesive, enabling grains to more easily move relative to each other, and macrofaunal burrowers use fluidization or plastic rearrangement of grains. In both sand and mud, peristaltic movements apply normal forces and reduce shear. Excavation and localized grain compaction are mechanisms that plastically deform sediments and are effective in both mud and sand, with bulk excavation being used by larger organisms and localized compaction by smaller organisms. Mechanical boring of hard substrata is an extreme form of excavation in which no compaction of burrow walls occurs and grains are abraded with rigid, hard structures. Chemical boring involves secretion to dissolve or soften generally carbonate substrata. Despite substantial differences in the mechanics of the media, similar burrowing behaviors are effective in mud and sand.

  18. Localized fluidization burrowing mechanics of Ensis directus.

    Science.gov (United States)

    Winter, Amos G; Deits, Robin L H; Hosoi, A E

    2012-06-15

    Muscle measurements of Ensis directus, the Atlantic razor clam, indicate that the organism only has sufficient strength to burrow a few centimeters into the soil, yet razor clams burrow to over 70 cm. In this paper, we show that the animal uses the motions of its valves to locally fluidize the surrounding soil and reduce burrowing drag. Substrate deformations were measured using particle image velocimetry (PIV) in a novel visualization system that enabled us to see through the soil and watch E. directus burrow in situ. PIV data, supported by soil and fluid mechanics theory, show that contraction of the valves of E. directus locally fluidizes the surrounding soil. Particle and fluid mixtures can be modeled as a Newtonian fluid with an effective viscosity based on the local void fraction. Using these models, we demonstrate that E. directus is strong enough to reach full burrow depth in fluidized soil, but not in static soil. Furthermore, we show that the method of localized fluidization reduces the amount of energy required to reach burrow depth by an order of magnitude compared with penetrating static soil, and leads to a burrowing energy that scales linearly with depth rather than with depth squared.

  19. Den canadiske model

    DEFF Research Database (Denmark)

    Böss, Michael

    2009-01-01

    Det har altid været en amerikansk fordom, at Canada er et kedeligt land. Men i lyset af den finansielle krise, er den fordom sværere at holde fast i. Nabolandet mod nord, hvor hverken socialisme eller radikal liberalisme har nydt stor udbredelse, og hvor den finansielle sektor i lang tid har være...

  20. Den kommunikerende organisation

    DEFF Research Database (Denmark)

    Tække, Jesper

    2006-01-01

    samtidig tilbydes optimale muligheder for at få opfyldt individuelle behov og karrieremuligheder. For at en organisation skal kunne korrigere sig i forhold til de krav den konfronteres med, må der kunne fremstilles et adækvat billede af den. Det vil sige at dens faktiske kommunikationsprocesser må kunne...... drages frem i lyset på en måde så hensigtsmæssigheder og uhensigtsmæssigheder kan iagttages og selv blive objekt for reflekteret organisationskommunikation. Dette paper giver et udkast til en analysestrategi, hvormed der kan tegnes et billede af den enkelte organisation ud fra hvordan dens enkelte og...

  1. Application of morphologic burrow architects: lungfish or crayfish?

    Science.gov (United States)

    Hasiotis, Stephen T.; Mitchell, Charles E.; Dubiel, Russell R.

    1993-01-01

    A methodology for trace fossil identification using burrowing signatures is tested by evaluating ancient and modern lungfish and crayfish burrows and comparing them to previously undescribed burrows in a stratigraphic interval thought to contain both lungfish and crayfish burrows. Permian burrows that bear skeletal remains of the lungfish Gnathorhiza, from museum collections, were evaluated to identify unique burrow morphologies that could be used to distinguish lungfish from crayfish burrows when fossil remains are absent. The lungfish burrows were evaluated for details of the burrowing mechanism preserved in the burrow morphologies together forming burrowing signatures and were compared to new burrows in the Chinle Formation of western Colorado to test the methodology of using burrow signatures to identify unknown burrows. Permian lungfish aestivation burrows show simple, nearly vertical, unbranched architectures and relatively smooth surficial morphologies with characteristic quasi‐horizontal striae on the burrow walls and vertical striae on the bulbous terminus. Burrow lengths do not exceed 0.5 m. In contrast, modern and ancient crayfish burrows exhibit simple to highly complex architectures with highly textured surficial morphologies. Burrow lengths may reach 4 to 5 m. Burrow morphologies unlike those identified in Gnathorhiza aestivation burrows were found in four burrow groups from museum collections. Two of these groups exhibit simple architectures and horizontal striae that were greater in sinuosity and magnitude, respectively. One of these burrows contains the remains of Lysorophus, but the burrow surface reveals no reliable surficial characteristics. It is not clear whether Lysorophus truly burrowed or merely occupied a pre‐existing structure. The other two groups exhibit surficial morphologies similar to those found on modern and ancient crayfish burrows and may provide evidence of freshwater crayfish in the Permian. Burrows from the Upper Triassic

  2. Burrowing Owl - Palo Verde Valley [ds197

    Data.gov (United States)

    California Department of Resources — These burrowing owl observations were collected during the spring and early summer of 1976 in the Palo Verde Valley, eastern Riverside County, California. This is an...

  3. The burrowing origin of modern snakes

    Science.gov (United States)

    Yi, Hongyu; Norell, Mark A.

    2015-01-01

    Modern snakes probably originated as habitat specialists, but it controversial unclear whether they were ancestrally terrestrial burrowers or marine swimmers. We used x-ray virtual models of the inner ear to predict the habit of Dinilysia patagonica, a stem snake closely related to the origin of modern snakes. Previous work has shown that modern snakes perceive substrate vibrations via their inner ear. Our data show that D. patagonica and modern burrowing squamates share a unique spherical vestibule in the inner ear, as compared with swimmers and habitat generalists. We built predictive models for snake habit based on their vestibular shape, which estimated D. patagonica and the hypothetical ancestor of crown snakes as burrowers with high probabilities. This study provides an extensive comparative data set to test fossoriality quantitatively in stem snakes, and it shows that burrowing was predominant in the lineages leading to modern crown snakes. PMID:26702436

  4. The burrowing origin of modern snakes.

    Science.gov (United States)

    Yi, Hongyu; Norell, Mark A

    2015-11-01

    Modern snakes probably originated as habitat specialists, but it controversial unclear whether they were ancestrally terrestrial burrowers or marine swimmers. We used x-ray virtual models of the inner ear to predict the habit of Dinilysia patagonica, a stem snake closely related to the origin of modern snakes. Previous work has shown that modern snakes perceive substrate vibrations via their inner ear. Our data show that D. patagonica and modern burrowing squamates share a unique spherical vestibule in the inner ear, as compared with swimmers and habitat generalists. We built predictive models for snake habit based on their vestibular shape, which estimated D. patagonica and the hypothetical ancestor of crown snakes as burrowers with high probabilities. This study provides an extensive comparative data set to test fossoriality quantitatively in stem snakes, and it shows that burrowing was predominant in the lineages leading to modern crown snakes.

  5. Misty – museets nye dinosaur

    DEFF Research Database (Denmark)

    Lindow, Bent Erik Kramer

    2014-01-01

    I november 2013 fi k Statens Naturhistoriske Museum en 16 meter lang julegave – det meget velbevarede skelet af en langhalset dinosaur med kælenavnet ’Misty’. Købet af det enorme skelet var muligt takket være en meget generøs gave fra Det Obelske Familiefond. Denne artikel ser nærmere på Misty......, hvad man ved om langhalsede dinosaurer, og hendes fremtidige betydning for museets forskning og formidling....

  6. What do giant titanosaur dinosaurs and modern Australasian megapodes have in common?

    Science.gov (United States)

    Grellet-Tinner, Gerald; Fiorelli, Lucas E.

    2015-01-01

    Titanosauria is a globally distributed clade of sometimes extremely large Mesozoic herbivorous sauropod dinosaurs. On the basis of current evidence these giant dinosaurs seem to have reproduced in specific and localized nesting sites. However, no investigations have been performed to understand the possible ecological and geological biases that acted for the selection of these nesting sites worldwide. In this study, observations were performed on the best-known Cretaceous nesting sites around the world. Our observations strongly suggest their eggs were incubated with environmental sources of heat, in burial conditions. Taking into account the clutch composition and geometry, the nature and properties of the sediments, the eggshells’ structures and conductance, it would appear that titanosaurs adopted nesting behaviors comparable to the modern Australasian megapodes, using burrow-nesting in diverse media and mound-building strategies. PMID:26623184

  7. The extinction of the dinosaurs.

    Science.gov (United States)

    Brusatte, Stephen L; Butler, Richard J; Barrett, Paul M; Carrano, Matthew T; Evans, David C; Lloyd, Graeme T; Mannion, Philip D; Norell, Mark A; Peppe, Daniel J; Upchurch, Paul; Williamson, Thomas E

    2015-05-01

    Non-avian dinosaurs went extinct 66 million years ago, geologically coincident with the impact of a large bolide (comet or asteroid) during an interval of massive volcanic eruptions and changes in temperature and sea level. There has long been fervent debate about how these events affected dinosaurs. We review a wealth of new data accumulated over the past two decades, provide updated and novel analyses of long-term dinosaur diversity trends during the latest Cretaceous, and discuss an emerging consensus on the extinction's tempo and causes. Little support exists for a global, long-term decline across non-avian dinosaur diversity prior to their extinction at the end of the Cretaceous. However, restructuring of latest Cretaceous dinosaur faunas in North America led to reduced diversity of large-bodied herbivores, perhaps making communities more susceptible to cascading extinctions. The abruptness of the dinosaur extinction suggests a key role for the bolide impact, although the coarseness of the fossil record makes testing the effects of Deccan volcanism difficult.

  8. The precise temporal calibration of dinosaur origins

    OpenAIRE

    Marsicano, Claudia A.; Irmis, Randall B.; Mancuso, Adriana C.; Mundil, Roland; Chemale, Farid

    2015-01-01

    Many hypotheses have been put forth to explain the origin and early radiation of dinosaurs, but poor age constraints for constituent fossil assemblages make these scenarios difficult to test. Using precise radioisotopic ages, we demonstrate that the temporal gap between assemblages containing only dinosaur precursors and those with the first dinosaurs was 5–10 million years shorter than previously thought. Thus, these data suggest that the origin of dinosaurs was a relatively rapid evolutiona...

  9. Den situationsbestemte bolig

    DEFF Research Database (Denmark)

    Duelund Mortensen, Peder

    2010-01-01

    Boligen er en del af vores forbrugsmønster, mere og mere uforudsigeligt og præget af tilfældigheder, stemninger og den situation, den enkelte befinder sig i. Dette stiller forskellige krav til den samme bolig, krav om individuel fortolkning, fleksibilitet og åbne anvendelsesmuligheder. Ud fra ana...... analyser af boliger i Pærehaven og VM-huset karakteriseres boligen som et dynamisk projekt rettet mod opbygning af identitet og arkitektonisk kvalitet....

  10. Den moderne patient

    DEFF Research Database (Denmark)

    Lassen, Trine

    2012-01-01

    Kapitlet indkredser, hvordan vi som sundhedsprofessionelle kan forklare den moderne patient. I særdeleshed lægges vægt på definerende faktorer i skabelsen af den patient vi møder i sundhedsvæsnet i dag. Kapitlet giver forskellige teoretiske bud på, hvordan man som sundhedsprofessionel kan anskue...... den moderne, nutidige patienter samt en kortere beskrivelse af, hvordan patienten tidligere er blev anskuet....

  11. Den inkluderende skole

    DEFF Research Database (Denmark)

    Hedegaard Hansen, Janne

    2009-01-01

    Artiklen tager afsæt i en forståelse af inklusion som den enkelte elevs ret til deltagelse i de eksisterende fællesskaber, forstået som de læringsrum, der bedst muligt tilgodeser den enkelte elevs særlige behov. I artiklen diskuteres hvilke nødvendige forandringer det fordrer i den pædagogiske pr...

  12. "Den onde kvinde"

    DEFF Research Database (Denmark)

    Holst, Søren

    2002-01-01

    Et af Dødehavsskrifterne, af den første udgiver kaldet "Den onde kvindes rænker" (4Q184), beskriver en svigefuld kvinde, der lokker fromme mænd i fordærv. Artiklen gennemgår tekstens fortolkningshistorie og påviser den rolle, det har spillet for læsningen, at teksten a priori er blevet opfattet s...

  13. Comment on "Evidence for mesothermy in dinosaurs".

    Science.gov (United States)

    Myhrvold, Nathan P

    2015-05-29

    Grady et al. (Reports, 13 June 2014, p. 1268) studied dinosaur metabolism by comparison of maximum somatic growth rate allometry with groups of known metabolism. They concluded that dinosaurs exhibited mesothermy, a metabolic rate intermediate between endothermy and ectothermy. Multiple statistical and methodological issues call into question the evidence for dinosaur mesothermy.

  14. The Development of a Virtual Dinosaur Museum

    Science.gov (United States)

    Tarng, Wernhuar; Liou, Hsin-Hun

    2007-01-01

    The objective of this article is to study the network and virtual reality technologies for developing a virtual dinosaur museum, which provides a Web-learning environment for students of all ages and the general public to know more about dinosaurs. We first investigate the method for building the 3D dynamic models of dinosaurs, and then describe…

  15. Den store skandinaviske redningsaktion

    DEFF Research Database (Denmark)

    Christensen, Claus Bundgård

    2015-01-01

    Historikeren Bo Lidegaard fortæller flot den store historie om den forbløffende og komplicerede skandinaviske redning af fanger fra Hitlers koncentrationslejre. En historie, der samtidig berører alvorlige moralske spørgsmål.......Historikeren Bo Lidegaard fortæller flot den store historie om den forbløffende og komplicerede skandinaviske redning af fanger fra Hitlers koncentrationslejre. En historie, der samtidig berører alvorlige moralske spørgsmål....

  16. Den Danske Regnskabsordbog

    DEFF Research Database (Denmark)

    Nielsen, Sandro; Mourier, Lise; Bergenholtz, Henning

    Den Danske Regnskabsordbog har 4.100 opslagsord og ca. 15.000 ordforbindelser. Ordbøgerne bygger primært på den gældende danske årsregnskabslov, danske regnskabsvejledninger og internationale regnskabsstandarder (IAS/IFRS).......Den Danske Regnskabsordbog har 4.100 opslagsord og ca. 15.000 ordforbindelser. Ordbøgerne bygger primært på den gældende danske årsregnskabslov, danske regnskabsvejledninger og internationale regnskabsstandarder (IAS/IFRS)....

  17. Biogeochemical consequences of macrofauna burrow ventilation†

    Directory of Open Access Journals (Sweden)

    Furukawa Yoko

    2001-10-01

    Full Text Available The burrow walls created by macrofauna in aquatic sediments are sites of intense chemical mass transfer. Quantitative measurement of their significance is, however, difficult because chemistry in the immediate vicinity of burrow walls is temporally dynamic due to periodic ventilation of burrows by macrofauna. A temporally dynamic, 2D multicomponent diffusion-reaction model was utilized to depict the magnitude and time dependency of chemical mass transfer in the immediate vicinity of burrow walls as well as at the water/sediment interface. The simulation results illustrate that sediment particles, pore water, and microorganisms within a few millimeters of burrow walls experience significant oscillation in pH (as much as two pH units and dissolved oxygen concentration (between saturation and near anoxia whereas such oscillation is absent at the water/ sediment interface. The geochemical oscillation is expected to affect the net stability of mineral phases, activities and community structures of microorganisms, and rates and magnitudes of microbial diagenetic reactions.

  18. Den Legende Organisation

    DEFF Research Database (Denmark)

    Thorsted, Ann Charlotte

    Bogen beskriver, hvordan to vidt forskellige organisationer - den store internationale virksomhed LEGO og den mindre nonprofit organisation SUS - har bragt legen i spil. Ann Charlotte Thorsted viser i bogen, hvordan leg kan understøtte innovation, læring, kommunikation, samarbejde og det gode arb...

  19. Den ideelle leder

    DEFF Research Database (Denmark)

    Holmgreen, Lise-Lotte

    2013-01-01

    af jobannoncer for lederstillinger på de danske jobportaler Stepstone og Job Index indikerer, at den første type er den, der oftest bliver efterspurgt blandt danske virksomheder (Holmgreen, i proces). Med udgangspunkt i begrebet framing (Evans & Green 2006; Fillmore 1982; Kövecses 2006; Lakoff 1987...

  20. Den Akutte Patient

    DEFF Research Database (Denmark)

    Graumann, Ole; Laursen, Christian B.

    2016-01-01

    Kapitlet indledes med en generel introduktion til de mest almindelige former for PoC-billeddiagnostik, hvor klinikeren i en akutmodtageafdeling selv varetager den initiale tolkning. Der fokuseres på de billeddiagnostiske undersøgelser, der kan og skal ske i den akutte modtageafdeling, og begrebet...

  1. Den levende sangfugl

    DEFF Research Database (Denmark)

    Bjerre, Thomas Ærvold

    2009-01-01

    Kronik om Harper Lee's roman "Dræb ikke en sangfugl" (1960) og den store indflydelse bog og film har haft på amerikansk kultur. Udgivelsesdato: 30. juli......Kronik om Harper Lee's roman "Dræb ikke en sangfugl" (1960) og den store indflydelse bog og film har haft på amerikansk kultur. Udgivelsesdato: 30. juli...

  2. Den moderate revolution

    DEFF Research Database (Denmark)

    Larsen, Bøje

    "normale" industrivirksomheder, men den er absolut set begrænset. Årsagerne til denne kun "moderate revolution" af organisationsformerne diskuteres: Er det fordi klassisk organisation og social nærkontakt er nødvendig i den nye økonomi, eller er det manglende fantasi og tryghedsbehov? Begge muligheder...

  3. Den lille levnedsmiddeltabel

    DEFF Research Database (Denmark)

    Saxholt, Erling; Fagt, Sisse; Matthiessen, Jeppe;

    Den lille levnedsmiddeltabel er en oversigt over indholdet af næringsstoffer i næsten 600 af de mest anvendte fødevarer i den danske kost. Herudover rummer bogen anvisninger til anvendelsen af fødevaredata....

  4. Den historiske krimi

    DEFF Research Database (Denmark)

    Agger, Gunhild

    2014-01-01

    Rent kvantitativt har den historiske og samtidshistoriske krimi ekspanderet voldsomt siden 1980’erne – også i Norden. Det er sket i forskellige medier, men mest fremtrædende i romanform. En historisk krimi er helt grundlæggende et værk, der kombinerer to genrer – krimien og den historiske roman. ...

  5. Den positive psykologis metoder

    DEFF Research Database (Denmark)

    Andersen, Frans Ørsted; Mørck, Line Lerche; Nissen, Poul Erik

    En antologi der giver en introduktion til en række af de metoder der anvendes til forskning, assessment, test, udviklingsarbejde og intervention indenfor den positive psykologi.......En antologi der giver en introduktion til en række af de metoder der anvendes til forskning, assessment, test, udviklingsarbejde og intervention indenfor den positive psykologi....

  6. Den kinesiske krimi

    DEFF Research Database (Denmark)

    Hansen, Kim Toft

    oversætter orientalisten Robert van Gulik den overleverede kinesiske fortælling De goong an til engelsk – som The Celebrated Cases of Judge Dee – og er dermed en central aktør i importen af den kinesiske krimi til vesten. Gulik stopper dog ikke her, men fortsætter sin fascination af karakteren Dommer Dee, og...... skriver derfor en række romaner, der foregår på det tidspunkt, som den biografiske Dee skal have levet. Gulik både oversætter, importerer og adapterer på den måde den kinesiske krimi. Dette paper sætter fokus på forskelle og ligheder på vestlig og kinesisk krimi – med særligt fokus på Dee goong...

  7. First dinosaurs from Saudi Arabia.

    Directory of Open Access Journals (Sweden)

    Benjamin P Kear

    Full Text Available Dinosaur remains from the Arabian subcontinent are exceedingly rare, and those that have been documented manifest indeterminate affinities. Consequently the discovery of a small, but diagnostic, accumulation of elements from Campanian-Maastrichtian (~ 75 Ma deposits in northwestern Saudi Arabia is significant because it constitutes the first taxonomically identifiable dinosaur material described from the Arabian Peninsula. The fossils include a series of possible lithostrotian titanosaur caudal vertebrae, and some isolated theropod marginal teeth that share unique character states and metric parameters (analyzed using multivariate statistical methods with derived abelisaurids - this is the first justifiable example of a non-avian carnivorous dinosaur clade from Arabia. The recognition of titanosaurians and abelisaurids from Saudi Arabia extends the palaeogeographical range of these groups along the entire northern Gondwanan margin during the latest Cretaceous. Moreover, given the extreme paucity of coeval occurrences elsewhere, the Saudi Arabian fossils provide a tantalizing glimpse into dinosaurian assemblage diversity within the region.

  8. Den egyptiske balancegang

    OpenAIRE

    Danielsen, Claus; Eilersen, Thore West; Rasmussen, Peter Henning; Kennedy, Ian Christian; Hansen, Mikala Sejer

    2008-01-01

    Opgaven er en undersøgelse af de omstændigheder Egypten stod i, da den palæstinensiske organisation Hamas valgte at sprænge grænsehegnet mellem Egypten og Gaza-striben den 23. januar 2008. Derfor er der i opgaven en tese om, at Egypten forsøger at bevare en magtmæssig status quo i regionen. Den historiske empiri er derfor med til at dokumentere Egyptens skiftende udenrigspolitik. Teoretisk er opgaven baseret på realismen og i særdeleshed Kenneth N. Waltz begreb om balance of power og status q...

  9. Den fleksible leders identitetsarbejde

    DEFF Research Database (Denmark)

    Madsen, Charlotte Øland

    2012-01-01

    Den lingvistiske drejning i organisationsforskningen giver nye perspektiver også på forskning indenfor organisering og ledelse (Boje 1995, Alvesson et. al. 2000b). Udviklingen af sprogforskningen (Wittgenstein 1953), og diskursteorien (Derrida 1976, Foucault 1979), den narrative teori (Boje 1995......, Boje et. al. 2004) samt en ny og spændende form for socialpsykologi (Potter et. al., 1987, Gergen 2011) beskrives i denne konferenceartikel som en alternativ måde at se organiseringsprocesser og ledelse på. Temaet i konferenceartiklen er hvordan den socialkonstruktionistiske tilgang kan bidrage til...

  10. Den Gode Historie

    DEFF Research Database (Denmark)

    Mogensen, T.E.

    den nysgerrige læser af trilogien. Den kan beses og bestilles på: www.universitypress.dk/DK/detail.php?token=73278292116&R=8778387078&N=nej ELLER KØB DEN DIREKTE HOS MIG: SLAGTILBUD 100 kr. (inkl. porto og forsendelse)!                            Henvendelse pr. e-mail til tine.engel@gmail.com...

  11. Allometry in dinosaurs and mammals

    Science.gov (United States)

    Lee, Scott

    2015-03-01

    The proportions of the leg bones change as the size of an animal becomes larger since the mass of the animal increases at a faster rate than the cross-sectional area of its leg bones. For the case of elastic similarity (in which the longitudinal stress in the legs remains constant in animals of all sizes), the diameter d and length L of the femur should be related as d = A L3/2. For geometric similarity (in which all dimensions are scaled by the same factor), d = A L. For animals with femora longer than 20 cm, we find the power law relationship to be d = A Lb with b = 1.13 +/- 0.06 for extant mammals (the largest mammal being Loxodonta africana with a 1.00-m-long femur) and b = 1.18 +/- 0.02 for dinosaurs (the largest dinosaur being Brachiosaurus brancai with a 2.03-m-long femur). These data show that extinct dinosaurs and extant animals scale in the same basic manner. The large sauropods (with femora twice as long as found in elephants) scale in a manner consistent with extrapolation of the scaling shown by extant mammals. These results argue that extinct dinosaurs moved in a manner very similar to extant mammals.

  12. Denver District Laboratory (DEN)

    Data.gov (United States)

    Federal Laboratory Consortium — Program CapabilitiesDEN-DO Laboratory is a multi-functional laboratory capable of analyzing most chemical analytes and pathogenic/non-pathogenic microorganisms found...

  13. Den antikke katapults udvikling

    DEFF Research Database (Denmark)

    Paasch, Kasper

    2011-01-01

    Hvordan bygger man en katapult? Dette spørgsmål belyses ved at se på den græske og romerske katapults udviklingshistorie samt på den forskningshistoriske tilgang til emnet, hovedsageligt set ud fra et ingeniørmæssig/matematisk synspunkt. Katapulten menes opfundet år 399 f.Kr. og blot ca. 120-150 ...

  14. Den signede dag

    DEFF Research Database (Denmark)

    Balslev-Clausen, Peter

    2010-01-01

    Artiklen gennemgår de tre middelalderlige versioner af den fællesnordiske dagvise fra 14. århundrede og gør rede for salmens tekst- og receptionshistorie i Dansk tradition.......Artiklen gennemgår de tre middelalderlige versioner af den fællesnordiske dagvise fra 14. århundrede og gør rede for salmens tekst- og receptionshistorie i Dansk tradition....

  15. EF & den sociale dimension

    DEFF Research Database (Denmark)

    Due, Jesper Jørgen; Madsen, Jørgen Steen; Jensen, Carsten Strøby

    En analyse af EU's institutioner og udviklingen af den sociale dimension i forbindelse med etbaleringen af det indre marked med særlig henblik på effekterne på det danske aftalesystem.......En analyse af EU's institutioner og udviklingen af den sociale dimension i forbindelse med etbaleringen af det indre marked med særlig henblik på effekterne på det danske aftalesystem....

  16. Den Danske Begrebsordbog

    DEFF Research Database (Denmark)

    Nimb, Sanni; Trap-Jensen, Lars; Lorentzen, Henrik;

    Den Danske Begrebsordbog er en ordbog, der er ordnet systematisk efter begreb, dvs. at ordene er grupperet efter deres betydning og ikke alfabetisk.Ordbogen indeholder næsten 200.000 ord og udtryk, og den dækker alt mellem himmel og jord såsom tid og rum, følelser og tænkning, samfund og...

  17. Den Lille Leder

    DEFF Research Database (Denmark)

    Juhl, Martin; Ussing, Lene Faber

    En lille lommebog, der i fem trin hjælper dig som projektleder til succesfulde projekter i entreprenørbranchen. "Den lille leder" indeholder udvalgte ledelsesteorier, der er relevante for projektledere i byggebranchen.......En lille lommebog, der i fem trin hjælper dig som projektleder til succesfulde projekter i entreprenørbranchen. "Den lille leder" indeholder udvalgte ledelsesteorier, der er relevante for projektledere i byggebranchen....

  18. Healthies er den nye selfie

    DEFF Research Database (Denmark)

    Fausing, Bent

    2015-01-01

    Om den sunde selfie, healthien. Om årsagne til dens opståen, succes og visuelt kulturelle og æstetiske betydning på de sociale medier.......Om den sunde selfie, healthien. Om årsagne til dens opståen, succes og visuelt kulturelle og æstetiske betydning på de sociale medier....

  19. Den digitale (r)evolution

    DEFF Research Database (Denmark)

    Pedersen, Rasmus Rex

    2016-01-01

    Dette kapitel undersøger hvordan den såkaldte ’digitale revolution’ af musikindustrierne har påvirket institutionelle og organisatoriske vilkår i den danske musikbranche. Gennem analyse af omsætningstal fra forskellige sektorer i den danske musikbranche udfordres den dominerende opfattelse af en...

  20. Gondwanan dinosaur evolution and biogeographic analysis

    Science.gov (United States)

    Forster, Catherine A.

    Gondwanan dinosaurs, though less well-known than their Laurasian counterparts,are being discovered and described at an ever accelerating pace. Dinosaurs are known from every major Gondwanan landmass, including South America, Africa, Antarctica, Australia, India, Madagascar and New Zealand. Much of the Gondwanan dinosaur literature includes speculation on vicariant and dispersal events relating to the fragmentation of Gondwana during the Jurassic and Cretaceous. These prolific biogeographic hypotheses are often inconclusive, speculative in nature, and untestable with the data at hand. To formulate well-supported biogeographic hypotheses, resolved dinosaur phylogenies and sound hypotheses of Earth history are necessary. Other factors, such as taphonomy, depositional setting, and missing taxonomic, temporal and geographic data, also contribute to understanding dinosaur faunal compositions. Additional phylogenetic information, a continuation of the current exploration and discovery, and knowledge of recent advances in tectonic plate reconstructions are paramount to developing a well-supported view of Gondwanan dinosaur biogeography.

  1. The Evolution and Extinction of the Dinosaurs

    Science.gov (United States)

    Fastovsky, David E.; Weishampel, David B.

    2005-02-01

    Written for non-specialists, this detailed survey of dinosaur origins, diversity, and extinction is designed as a series of successive essays covering important and timely topics in dinosaur paleobiology, such as "warm-bloodedness," birds as living dinosaurs, the new, non-flying feathered dinosaurs, dinosaur functional morphology, and cladistic methods in systematics. Its explicitly phylogenetic approach to the group is that taken by dinosaur specialists. The book is not an edited compilation of the works of many individuals, but a unique, cohesive perspective on Dinosauria. Lavishly illustrated with hundreds of new, specially commissioned illustrations by John Sibbick, world-famous illustrator of dinosaurs, the volume includes multi-page drawings as well as sketches and diagrams. First edition Hb (1996): 0-521-44496-9 David E. Fastovsky is Professor of Geosciences at the University of Rhode Island. Fastovsky, the author of numerous scientific publications dealing with Mesozoic vertebrate faunas and their ancient environments, is also scientific co-Editor of Geology. He has undertaken extensive fieldwork studying dinosaurs and their environments in Montana, North Dakota, Arizona, Mexico, and Mongolia. David B. Weishampel is a professor at the Center for Functional Anatomy and Evolution at Johns Hopkins University, School of Medicine. Weishampel is best known for discovering, researching, and naming several rare European dinosaur species. During the 1980s Weishampel gained fame for his work with American paleontologist Jack Horner and later named the famous plant-eating, egg-laying Orodromeus, Horner. Now, a decade after his pioneering studies with Horner, Weishampel is most widely known for his current work on the Romanian dinosaur fauna. He is the author and co-author of many titles, including The Dinosaur Papers, 1676-1906 (Norton, 2003); The Dinosauria, (University of California, 1990); and Dinosaurs of the East Coast, (Johns Hopkins University Press, 1996).

  2. Den digitale patient

    DEFF Research Database (Denmark)

    Dahl, Mads Ronald; birkler, jacob

    Den digitale patient tager afsæt i en ny verden: Patienten er blevet digitaliseret! Men hvem og hvad er den digitale patient, og hvornår og hvordan bliver den enkelte borger til en digital patient? Bogen indkredser patientens nye digitale identitet, som kan skabe grobund for en fælles forståelse og...... tværfagligt samarbejde mellem forskellige faggrupper. Bogens målgruppe er alle, som arbejder professionelt med sundhed og sundhedsvæsenet i Danmark. Det gælder på grunduddannelsesniveau, i forhold til efter- og videreuddannelse samt i klinisk praksis og blandt praktikere. Den digitale patient er skrevet ud...... fra et patientperspektiv, og ideen er at synliggørelse de mange udfordringer og konsekvenser, sundhedsinformatikken er svanger med. Bogen beskriver ikke blot den digitale patients fremtid, men fokuserer især på en række forhold og forbehold, der bør medtænkes, når nye elektroniske kommunikationsveje...

  3. The origin and early radiation of dinosaurs

    Science.gov (United States)

    Brusatte, Stephen L.; Nesbitt, Sterling J.; Irmis, Randall B.; Butler, Richard J.; Benton, Michael J.; Norell, Mark A.

    2010-07-01

    Dinosaurs were remarkably successful during the Mesozoic and one subgroup, birds, remain an important component of modern ecosystems. Although the extinction of non-avian dinosaurs at the end of the Cretaceous has been the subject of intense debate, comparatively little attention has been given to the origin and early evolution of dinosaurs during the Late Triassic and Early Jurassic, one of the most important evolutionary radiations in earth history. Our understanding of this keystone event has dramatically changed over the past 25 years, thanks to an influx of new fossil discoveries, reinterpretations of long-ignored specimens, and quantitative macroevolutionary analyses that synthesize anatomical and geological data. Here we provide an overview of the first 50 million years of dinosaur history, with a focus on the large-scale patterns that characterize the ascent of dinosaurs from a small, almost marginal group of reptiles in the Late Triassic to the preeminent terrestrial vertebrates of the Jurassic and Cretaceous. We provide both a biological and geological background for early dinosaur history. Dinosaurs are deeply nested among the archosaurian reptiles, diagnosed by only a small number of characters, and are subdivided into a number of major lineages. The first unequivocal dinosaurs are known from the late Carnian of South America, but the presence of their sister group in the Middle Triassic implies that dinosaurs possibly originated much earlier. The three major dinosaur lineages, theropods, sauropodomorphs, and ornithischians, are all known from the Triassic, when continents were joined into the supercontinent Pangaea and global climates were hot and arid. Although many researchers have long suggested that dinosaurs outcompeted other reptile groups during the Triassic, we argue that the ascent of dinosaurs was more of a matter of contingency and opportunism. Dinosaurs were overshadowed in most Late Triassic ecosystems by crocodile-line archosaurs and

  4. Den formbare seksualitet

    DEFF Research Database (Denmark)

    Lützen, Karin Cohr

    2016-01-01

    Den amerikanske sociolog John Gagnon så seksualiteten som noget, vi lærer af vores omgivelser, ligesom vi lærer at spille tennis eller at spise snegle. Karin Lützen mindes en ven og et forbillede.......Den amerikanske sociolog John Gagnon så seksualiteten som noget, vi lærer af vores omgivelser, ligesom vi lærer at spille tennis eller at spise snegle. Karin Lützen mindes en ven og et forbillede....

  5. Comment on "Evidence for mesothermy in dinosaurs".

    Science.gov (United States)

    D'Emic, M D

    2015-05-29

    Grady et al. (Reports, 13 June 2014, p. 1268) suggested that nonavian dinosaur metabolism was neither endothermic nor ectothermic but an intermediate physiology termed "mesothermic." However, rates were improperly scaled and phylogenetic, physiological, and temporal categories of animals were conflated during analyses. Accounting for these issues suggests that nonavian dinosaurs were on average as endothermic as extant placental mammals.

  6. Body size distribution of the dinosaurs.

    Directory of Open Access Journals (Sweden)

    Eoin J O'Gorman

    Full Text Available The distribution of species body size is critically important for determining resource use within a group or clade. It is widely known that non-avian dinosaurs were the largest creatures to roam the Earth. There is, however, little understanding of how maximum species body size was distributed among the dinosaurs. Do they share a similar distribution to modern day vertebrate groups in spite of their large size, or did they exhibit fundamentally different distributions due to unique evolutionary pressures and adaptations? Here, we address this question by comparing the distribution of maximum species body size for dinosaurs to an extensive set of extant and extinct vertebrate groups. We also examine the body size distribution of dinosaurs by various sub-groups, time periods and formations. We find that dinosaurs exhibit a strong skew towards larger species, in direct contrast to modern day vertebrates. This pattern is not solely an artefact of bias in the fossil record, as demonstrated by contrasting distributions in two major extinct groups and supports the hypothesis that dinosaurs exhibited a fundamentally different life history strategy to other terrestrial vertebrates. A disparity in the size distribution of the herbivorous Ornithischia and Sauropodomorpha and the largely carnivorous Theropoda suggests that this pattern may have been a product of a divergence in evolutionary strategies: herbivorous dinosaurs rapidly evolved large size to escape predation by carnivores and maximise digestive efficiency; carnivores had sufficient resources among juvenile dinosaurs and non-dinosaurian prey to achieve optimal success at smaller body size.

  7. Body size distribution of the dinosaurs.

    Science.gov (United States)

    O'Gorman, Eoin J; Hone, David W E

    2012-01-01

    The distribution of species body size is critically important for determining resource use within a group or clade. It is widely known that non-avian dinosaurs were the largest creatures to roam the Earth. There is, however, little understanding of how maximum species body size was distributed among the dinosaurs. Do they share a similar distribution to modern day vertebrate groups in spite of their large size, or did they exhibit fundamentally different distributions due to unique evolutionary pressures and adaptations? Here, we address this question by comparing the distribution of maximum species body size for dinosaurs to an extensive set of extant and extinct vertebrate groups. We also examine the body size distribution of dinosaurs by various sub-groups, time periods and formations. We find that dinosaurs exhibit a strong skew towards larger species, in direct contrast to modern day vertebrates. This pattern is not solely an artefact of bias in the fossil record, as demonstrated by contrasting distributions in two major extinct groups and supports the hypothesis that dinosaurs exhibited a fundamentally different life history strategy to other terrestrial vertebrates. A disparity in the size distribution of the herbivorous Ornithischia and Sauropodomorpha and the largely carnivorous Theropoda suggests that this pattern may have been a product of a divergence in evolutionary strategies: herbivorous dinosaurs rapidly evolved large size to escape predation by carnivores and maximise digestive efficiency; carnivores had sufficient resources among juvenile dinosaurs and non-dinosaurian prey to achieve optimal success at smaller body size.

  8. Dinosaur dynamics in the Jurassic Era

    Science.gov (United States)

    Lee, Scott

    2010-04-01

    Dinosaurs were fascinating animals and elicit much excitement in the classroom. Analysis of fossilized dinosaur trackways permits one to estimate the locomotion speeds and accelerations of these extinct beasts. Such analysis allows one to apply Newton's laws of motion to examples from the Jurassic Era.

  9. The precise temporal calibration of dinosaur origins

    Science.gov (United States)

    Marsicano, Claudia A.; Irmis, Randall B.; Mancuso, Adriana C.; Mundil, Roland; Chemale, Farid

    2016-01-01

    Dinosaurs have been major components of ecosystems for over 200 million years. Although different macroevolutionary scenarios exist to explain the Triassic origin and subsequent rise to dominance of dinosaurs and their closest relatives (dinosauromorphs), all lack critical support from a precise biostratigraphically independent temporal framework. The absence of robust geochronologic age control for comparing alternative scenarios makes it impossible to determine if observed faunal differences vary across time, space, or a combination of both. To better constrain the origin of dinosaurs, we produced radioisotopic ages for the Argentinian Chañares Formation, which preserves a quintessential assemblage of dinosaurian precursors (early dinosauromorphs) just before the first dinosaurs. Our new high-precision chemical abrasion thermal ionization mass spectrometry (CA-TIMS) U-Pb zircon ages reveal that the assemblage is early Carnian (early Late Triassic), 5- to 10-Ma younger than previously thought. Combined with other geochronologic data from the same basin, we constrain the rate of dinosaur origins, demonstrating their relatively rapid origin in a less than 5-Ma interval, thus halving the temporal gap between assemblages containing only dinosaur precursors and those with early dinosaurs. After their origin, dinosaurs only gradually dominated mid- to high-latitude terrestrial ecosystems millions of years later, closer to the Triassic-Jurassic boundary.

  10. The precise temporal calibration of dinosaur origins.

    Science.gov (United States)

    Marsicano, Claudia A; Irmis, Randall B; Mancuso, Adriana C; Mundil, Roland; Chemale, Farid

    2016-01-19

    Dinosaurs have been major components of ecosystems for over 200 million years. Although different macroevolutionary scenarios exist to explain the Triassic origin and subsequent rise to dominance of dinosaurs and their closest relatives (dinosauromorphs), all lack critical support from a precise biostratigraphically independent temporal framework. The absence of robust geochronologic age control for comparing alternative scenarios makes it impossible to determine if observed faunal differences vary across time, space, or a combination of both. To better constrain the origin of dinosaurs, we produced radioisotopic ages for the Argentinian Chañares Formation, which preserves a quintessential assemblage of dinosaurian precursors (early dinosauromorphs) just before the first dinosaurs. Our new high-precision chemical abrasion thermal ionization mass spectrometry (CA-TIMS) U-Pb zircon ages reveal that the assemblage is early Carnian (early Late Triassic), 5- to 10-Ma younger than previously thought. Combined with other geochronologic data from the same basin, we constrain the rate of dinosaur origins, demonstrating their relatively rapid origin in a less than 5-Ma interval, thus halving the temporal gap between assemblages containing only dinosaur precursors and those with early dinosaurs. After their origin, dinosaurs only gradually dominated mid- to high-latitude terrestrial ecosystems millions of years later, closer to the Triassic-Jurassic boundary.

  11. Den materielle drejning

    DEFF Research Database (Denmark)

    Skiveren, Tobias; Gregersen, Martin

    2015-01-01

    Ved at trække på en række forskellige tænkere som Jane Bennett, Arne Næss, Donna Haraway og Karan Barad relaterer artiklen den såkaldte materielle drejning til tre filosofisk-teoretiske nyorienteringer: økokritik, det posthumane og kropsmaterialisme. Tesen er, at interaktionenen mellem disse...

  12. Den danske regionskonstruktion

    DEFF Research Database (Denmark)

    Klausen, Kurt Klaudi

    Region Midtjylland er i centrum for analysen men den omfatter også regionsdannelsen i almindelighed. Der anlægges i analysen på samme tid et politologisk, organisationsteoretisk og økonomisk resonnement. Regionsdannelsen finder sted på baggrund af de setup Strukturreformen har sat, men udfoldes p...

  13. Den kaotiske organisation

    DEFF Research Database (Denmark)

    Helms, Niels Henrik

    2006-01-01

    Præsentation af den britiske organisationsteoretiker Ralph Stacey: Stacey mener samlet, at organisationer ikke skal ses som systemer, der opstår, når individer interagerer med hinanden. Det er selve interaktionen, der er organisationen. Staceys kernebegreb er temporære processer. Når vi interager...

  14. Den amerikanske udfordring

    DEFF Research Database (Denmark)

    Böss, Michael

    1994-01-01

    Artiklen beskriver den bulgarsk-franske tænker Tzvetan Todorovs udvikling fra litteraturteoretiker til bredt humanistisk engageret tænker. I artiklen argumenteres der for, at Todorovs bekendelse til oplysningshumanismen skal forstås på baggrund af hans personlige erfaringer fra en opvækst i det...

  15. Den patriarkalske Abraham

    DEFF Research Database (Denmark)

    Jensen, Hans Jørgen Lundager

    2015-01-01

    økonomi og slægtskabsrelationer. I Mary Douglas' Grid/Group-skema vil Abraham stå i samme grad fjernt fra præsteligt-hierarkiske og deuteronomistisk-enklavistiske idealer, De pietistiske og etnocentriske temaer som den bibelske tekstoverleveringsproces har tilføjet Abraham-figuren, har ikke tildækket en...

  16. Den personlige dimension

    DEFF Research Database (Denmark)

    Olsen, Jan Brødslev

    2009-01-01

    Personlig udvikling og kompetence er vigtige dimensioner i sygeplejerskeuddannelsen. Dette stiller krav til læringsmæssige metoder, som er specielt egenede til denne særlige undervisningsopgave. På baggrund af en række psykologiske og filosofiske inspirationskilder foreslåes den såkaldste...

  17. Den unge Burkes Satire

    DEFF Research Database (Denmark)

    Ørndorf, Steen

    Edmund Burke (1730-1797) er i nyere tid blevet politisk ikon, kendt som konservatismens fader. Berømmelsen skyldes hovedværket fra 1790, Reflections on the Revolution in France, som er et angreb på den franske revolution. Ungdomsarbejdet A Vindication of Natural Society er fra 1756 og har status...... både som konservativ forløber for Burkes hovedværk, og som radikalt modstykke hertil. Burkes fremragende sprogfornemmelse udfoldes her i et rent festfyrværkeri af besnærende argumenter. Den forførende retorik bedøver læserens fornuft. Denne virkning gør sig stadig gældende. Læst med fornuft, er det et......: "Forfatteren har et imponerende kendskab til Burkelitteraturen og til datidens engelske samfundsforhold. Behandlingen af Burke er kompetent og dybdegående. Stærkest er Ørndorfs diskussion af Burkes A Vindication of Natural Society og den receptionshistorie, der knytter sig til værket. Jeg er af den opfattelse...

  18. Den Akutte Patient

    DEFF Research Database (Denmark)

    Laursen, Christian B.; Graumann, Ole

    2016-01-01

    UL-vejledte teknikker til anlæggelse af dræn, katetre og karadgange samt til udtømning af væskefyldte hulrum præsenteres som point of care-procedurer, der på sigt bør indgå i det rutinemæssige arbejde i den akutte modtagelse....

  19. Den menneskelige eksistens

    DEFF Research Database (Denmark)

    tilværelse. Dermed tilbyder den et bedre grundlag for at forstå fremtrædende kultursociologiske og socialpsykologiske problemer som identitetsusikkerhed, angst og raseri såvel som frigørende muligheder for engagement og kreativitet. Foruden originale tekster af Merleau-Ponty, Ricœur og Waldenfels rummer...

  20. Den globale provins

    DEFF Research Database (Denmark)

    Gebauer, Mirjam

    2008-01-01

    »Den globale provins« gennemgår - med udgangspunkt i Ottmar Ettes begreb om at skrive mellem verdener - centrale værker fra denne migrationslitteratur. Ilija Trojanow kan med sin bulgarsk-sydafrikansk-østrigske baggrund beskrive en global verden mangfoldigt og komplekst, mens forfattere som Selim...

  1. Den sundhedsvidenskabelige opgave

    DEFF Research Database (Denmark)

    Lindahl, Marianne Pia; Juhl, Carsten Bogh

    troværdigheden af sine resultater. Bogen er opdateret, så den refererer til Microsoft Office 2013, og giver instruktioner og tips til: • Hvordan man bruger Word til hjælp med indholdsfortegnelse, overskrifter og korrektur • Hvordan man bruger Word til hjælp med diagrammer og tabeller• Hvordan man bruger Excel...

  2. Den relationelle psykiatri

    DEFF Research Database (Denmark)

    Kjølbye, Morten; Jacobsen, Claus Haugaard

    2009-01-01

    Dette kapitel bygger videre på kapitlet om det teoretiske grundlag for den relationelle psykiatri. I perspektiv af en mentaliseringsbaseret forståelse præsenteres en række psykopatologiske faktorer samt en model til forståelse af psykopatologisk udvikling. Ved inddragelse af kasuistisk materiale ...

  3. Burrowing Owl Monitoring Report for Calendar Year 2012

    Energy Technology Data Exchange (ETDEWEB)

    Wilde, Justin W.; Lindsey, Cole T.; Nugent, John J.

    2013-03-14

    The monitoring during 2012 focused on documenting the status of known burrows. Newly identified burrows were documented while examining historical locations, during ecological resource reviews, or discovered during other monitoring efforts. The timing of the monitoring effort allowed staff to perform the surveys without disrupting any breeding or hatching, while also allowing for easy discernment of adults from juveniles, which helped in determining burrow-use type.

  4. Kollegaerne er den nye chef

    DEFF Research Database (Denmark)

    Fugl, Marie

    2008-01-01

    Den tid, hvor chefen var den, der delte skideballer ud, er slut. Rollen som 'bad cop' er overtaget af kollegateamet, der med hård hånd sørger for, at den enkelte yder sin del. Udgivelsesdato: November...

  5. Den naturlige tillid og tilknytning

    DEFF Research Database (Denmark)

    Bo, Inger Glavind

    2008-01-01

    indstilling. Herved revurderes Alfred Schutz' begreb om den naturlige indstilling, idet tilliden nok er en del heraf og af den rutiniserede holdning i hverdagslivet, men også er rimelig skrøbelig og afhængig af del individets tidligere tilknytning, dels den fortsatte skabelse af ontologisk sikkerhed i...

  6. The last polar dinosaurs: high diversity of latest Cretaceous arctic dinosaurs in Russia.

    Science.gov (United States)

    Godefroit, Pascal; Golovneva, Lina; Shchepetov, Sergei; Garcia, Géraldine; Alekseev, Pavel

    2009-04-01

    A latest Cretaceous (68 to 65 million years ago) vertebrate microfossil assemblage discovered at Kakanaut in northeastern Russia reveals that dinosaurs were still highly diversified in Arctic regions just before the Cretaceous-Tertiary mass extinction event. Dinosaur eggshell fragments, belonging to hadrosaurids and non-avian theropods, indicate that at least several latest Cretaceous dinosaur taxa could reproduce in polar region and were probably year-round residents of high latitudes. Palaeobotanical data suggest that these polar dinosaurs lived in a temperate climate (mean annual temperature about 10 degrees C), but the climate was apparently too cold for amphibians and ectothermic reptiles. The high diversity of Late Maastrichtian dinosaurs in high latitudes, where ectotherms are absent, strongly questions hypotheses according to which dinosaur extinction was a result of temperature decline, caused or not by the Chicxulub impact.

  7. Den liberale tolerance

    DEFF Research Database (Denmark)

    Mchangama, Jacob; Andersen, Rasmus Fonnesbæk

    2012-01-01

    Tolerance er en kerneværdi i den liberal-demokratiske samfundsordenen, men i vor tid er det liberale tolerancebegreb om ikke at gribe ind i det, man ikke synes om, kommet under angreb fra flere sider, især som følge af problemer med indvandring og integration. Tolerance opfattes i stigende grad som...... begrænset tolerancebegreb igen bør træde i stedet for den multikulturalistisk inspirerede forståelse af tolerance, som er fremtrædende i dag, og som faktisk begrunder en institutionaliseret intolerance i form af en række begrænsninger på særligt ytringsfriheden....

  8. Den interkonfessionelle dialog

    DEFF Research Database (Denmark)

    Pedersen, Else Marie Wiberg

    2006-01-01

    På baggrund af en gennemgang af det 20. århundredes økumeniske hermeneutik, foreslås det i denne artikel, at den økumeniske dialog (et ord, som oversættes forskelligt af de forskellige konfessioner) erstattes af en økumenisk diskurs (jf. Michel de Certau og Lukas Vischer). Der plæderes således fo...

  9. Villavejen og dens muligheder

    DEFF Research Database (Denmark)

    Vedel-Petersen, F.

    Publikationen handler om hvordan villavejen kan tilføres nye kvaliteter, blive smukkere, mere oplevelsesrig og sikker for de mange der bor og færdes på vejen. Den beskriver en lille villavej, Hjortekærbakken, og indeholder desuden en række råd og anvisninger vedrørende planlægning af nye villavej...

  10. Den moderne russiske stat

    DEFF Research Database (Denmark)

    Hansen, Flemming Splidsboel

    Briefet er inddelt i tre hovedafsnit. I første del gennemgås de tre verdensordener kort, og Flemming Splidsboel forklarer hvorledes de forholder sig til hinanden. Derefter diskuteres det russiske syn på fire elementer fra de moderne og postmoderne verdensordener - suverænitet, magt, de nationale ...... interesser og individets status. Flemming Splidsboel slutter af med at præsentere nogle tanker vedrørende den fremtidige læring i Rusland....

  11. Den retoriske situation

    DEFF Research Database (Denmark)

    Hansen, Jette Barnholdt

    2009-01-01

    Artiklen, som er skrevet på baggrund af et oplæg, som jeg holdt på  Årsmødet for Sektionen for Gymnasium og HF i Helsingør, oktober 2009, plæderer for anvendelsen af Lloyd F. Bitzers teori om den retoriske situation i retorikundervisningen i gymnasiet. I artiklen benytter jeg Bitzers teori som en...

  12. Hvorfor den titel?

    DEFF Research Database (Denmark)

    Krejberg, Kasper Green

    2015-01-01

    Den skandaløse titel på Karl Ove Knausgårds store selvbiografi Min kamp 1-6 er ikke kun en provokation eller en ironisk kommentar, men udtryk for en gennemgående interesse for og fascination af nazismen. Artiklen ser denne fascination efter i sømmene og beskriver dermed, hvad formålet med referen...... referencen til Hitlers Mein Kampf kan være...

  13. Den Magiske Kugle

    DEFF Research Database (Denmark)

    Nørgaard, Bent

    2007-01-01

    og ikke skader kroppens sunde celler. Metoden går ud på at indkapsle kræftmedicin i bittesmå fedtkugler, såkaldt "magiske kugler". I forestillingen følger vi de magiske kuglers fantastiske rejse: Lige fra deres spæde fødsel som en vision fremsat af den tyske nobelprisvinder dr. Paul Ehrlich i...

  14. Den gamle verdens magi

    DEFF Research Database (Denmark)

    Holck, Jakob Povl

    I denne bog præsenterer forskningsbibliotekar cand.mag., ph.d. Jakob Povl Holck sjældne bøger og andre biblioteksmaterialer fra Herlufsholm-samlingen på Syddansk Universitetsbibliotek i Odense. Bogens form udgør en mosaik af værker i tekst og især billeder med speciel vægt på ’den videnskabelige ...

  15. Recent Progress in the Study of Dinosaur Eggs in China

    Institute of Scientific and Technical Information of China (English)

    WANG Qiang; WANG Xiaolin; ZHAO Zikui

    2010-01-01

    @@ Dinosaur eggs are a special type of vertebrate fossils.Despite their varied shapes,all dinosaur eggs are composed of eggshells,though the thickness of the shell may also vary.Dinosaur eggshells consist primarily of the mineral calcite(calcium carbonate).By studying dinosaur eggs,we can infer the reproductive system and behavior of dinosaurs and even the palaeoenvironment,palaeoclimate,palaeoecology in which they lived.Moreover,dinosaur eggs are useful for stratigraphic division and correlation as well as paleobiogeographic interpretations.

  16. Lower Cretaceous Dinosaur Tracks from Puebla, Mexico

    Directory of Open Access Journals (Sweden)

    Rubén A. Rodríguez-de la Rosa

    2012-01-01

    Full Text Available Dinosaur tracks have been identified near San Martín Atexcal, southern Puebla, Mexico, within the sedimentary sequence of the San Juan Raya Formation of Lower Cretaceous (Albian age. The tracksite, located in the bed of the Magdalena River, reveals six different ichnofossiliferous levels identified within a 9 m thick sedimentary sequence. The inferred environment is that of a tidal (marginal marine mudflat (Level I. Level I preserves three theropods trackways (?Allosauroidea, additionally, isolated tracks belonging to iguanodontids (Ornithopoda. Level II preserves faint iguanodontid tracks. Levels III to V preserve sauropod tracks. Younger level VI preserves, although morphologically different, a track belonging to Ornithopoda. The dinosaur tracks from San Martín Atexcal support the existence of continental facies within the San Juan Raya Formation; they represent the second record of dinosaur tracks from the Lower Cretaceous of Mexico and are part of an important but little documented record of Lower Cretaceous dinosaurs in Mexico.

  17. Dinosaurs in the year of Darwin.

    Science.gov (United States)

    Dodson, Peter

    2009-09-01

    This special issue of The Anatomical Record explores the recent advances in the functional morphology and paleobiology of dinosaurs. Although Darwin did not study dinosaurs because paleontology was in its infancy a century and half ago, he considered both paleontology and anatomy as essential subjects for establishing the validity of evolution. The study of dinosaurs constitutes a vigorous subdiscipline within vertebrate paleontology, and anatomists and evolutionary functional morphologists constitute an especially creative subgroup within dinosaur paleontology. The collection of 17 papers presented in this issue encompass cranial anatomy, postcranial anatomy, and paleobiology of dinosaurs and other archosaurs. Soft tissue subjects include studies of brain structure, jaw adductor muscles, and keratinous appendages of the skull. Taxonomically, it includes four papers with a focus on theropods, including Tyrannosaurus, five papers dealing with ceratopsians, three papers on hadrosaurs, and one on ankylosaurs. Modern anatomical techniques such as CT scanning, finite element analysis, and high resolution histology are emphasized. The visual presentation of results of these studies is spectacular. Results include the first-ever life history table of a plant-eating dinosaur; a determination of the head orientation of Tyrannosaurus and its relatives based on interpretation of the semicircular canals. The claws of Velociraptor appear to best adapted for tree climbing, but not for horrific predatory activities. Pachyrhinosaurus evidently used its massive head for head butting. The tail club of the armored dinosaur Euoplocephalus had the structural integrity to be used as a weapon. The pages abound with insights such as these. Dinosaurs once dead for millions of years live again!

  18. First Dinosaur Tracks from the Arabian Peninsula

    Science.gov (United States)

    Schulp, Anne S.; Al-Wosabi, Mohammed; Stevens, Nancy J.

    2008-01-01

    Background The evolutionary history of Mesozoic terrestrial vertebrates from the Arabian Peninsula is virtually unknown. Despite vast exposures of rocky outcrops, only a handful of fossils have yet been described from the region. Here we report a multi-taxon dinosaur track assemblage near Madar village, 47 km north of Sana'a, Republic of Yemen. This represents the first dinosaur tracksite from the Arabian Peninsula, and the only multi-taxon dinosaur ichnosite in the Middle East. Methodology/Findings Measurements were taken directly from trackway impressions, following standard ichnological conventions. The presence of bipedal trackmakers is evidenced by a long series of pes imprints preserving smoothly rounded posterior margins, no evidence of a hallux, bluntly rounded digit tips and digital divarication angles characteristic of ornithopod dinosaurs. Nearby, eleven parallel quadrupedal trackways document a sauropod herd that included large and small individuals traveling together. Based on the morphology of manus impressions along with a narrow-gauged stance, the quadrupedal trackways were made by non-titanosauriform neosauropods. Additional isolated tracks and trackways of sauropod and ornithopod dinosaurs are preserved nearby. Conclusions/Significance Taken together, these discoveries present the most evocative window to date into the evolutionary history of dinosaurs of the Arabian Peninsula. Given the limited Mesozoic terrestrial record from the region, this discovery is of both temporal and geographic significance, and massive exposures of similarly-aged outcrops nearby offer great promise for future discoveries. PMID:18493306

  19. Den naturfaglige evalueringskultur i folkeskolen

    DEFF Research Database (Denmark)

    Dolin, Jens; Krogh, Lars Brian

    2008-01-01

    Formålet med denne rapport er at etablere et grundlag for at kunne vurdere, hvorvidt PISAs testformat og tilgang til testning svarer til den evalueringskultur, der er fremherskende i naturfagene i de ældste klasser i den danske folkeskole.   Rapporten indledes med en kortfattet oversigt over nogl...... at tage PISA-science testen.   Rapporten slutter med en konklusion over de vigtigste resultater, hvor PISA-science testen sammenholdes med den danske evalueringskultur....

  20. Detecting Burrowing Owl Bloodmeals in Pulex irritans (Siphonaptera: Pulicidae).

    Science.gov (United States)

    Graham, Christine B; Eisen, Rebecca J; Belthoff, James R

    2016-03-01

    Pulex irritans L. is a cosmopolitan flea species that infests a wide variety of hosts. In North America it generally parasitizes large wild mammals, but in the Pacific Northwest an association has emerged between P. irritans and the western burrowing owl (Athene cunicularia hypugaea). While investigators have recognized this association for decades, it has not been clear if P. irritans feeds on burrowing owls, or if the owls serve exclusively as phoretic hosts. Here we describe using a real-time assay that was originally developed to identify bloodmeals in Ugandan cat fleas (Ctenocephalides felis Bouché) to detect burrowing owl DNA in P. irritans collected from burrowing owls in southern Idaho. Of 50 fleas tested, 12 had no detectable vertebrate bloodmeal. The remaining 38 (76%) contained burrowing owl DNA. The assay did not detect vertebrate DNA in unfed fleas exposed to owl or mouse pelts and is therefore unlikely to detect DNA in fleas from vertebrates that have served exclusively as phoretic hosts. We conclude that P. irritans feeds on burrowing owls. We discuss the potential implications of this finding for burrowing owl conservation and enzootic plague dynamics.

  1. Dinosaur evolution. A Jurassic ornithischian dinosaur from Siberia with both feathers and scales.

    Science.gov (United States)

    Godefroit, Pascal; Sinitsa, Sofia M; Dhouailly, Danielle; Bolotsky, Yuri L; Sizov, Alexander V; McNamara, Maria E; Benton, Michael J; Spagna, Paul

    2014-07-25

    Middle Jurassic to Early Cretaceous deposits from northeastern China have yielded varied theropod dinosaurs bearing feathers. Filamentous integumentary structures have also been described in ornithischian dinosaurs, but whether these filaments can be regarded as part of the evolutionary lineage toward feathers remains controversial. Here we describe a new basal neornithischian dinosaur from the Jurassic of Siberia with small scales around the distal hindlimb, larger imbricated scales around the tail, monofilaments around the head and the thorax, and more complex featherlike structures around the humerus, the femur, and the tibia. The discovery of these branched integumentary structures outside theropods suggests that featherlike structures coexisted with scales and were potentially widespread among the entire dinosaur clade; feathers may thus have been present in the earliest dinosaurs.

  2. Incorporation of microplastics from litter into burrows of Lumbricus terrestris.

    Science.gov (United States)

    Huerta Lwanga, Esperanza; Gertsen, Hennie; Gooren, Harm; Peters, Piet; Salánki, Tamás; van der Ploeg, Martine; Besseling, Ellen; Koelmans, Albert A; Geissen, Violette

    2017-01-01

    Pollution caused by plastic debris is an urgent environmental problem. Here, we assessed the effects of microplastics in the soil surface litter on the formation and characterization of burrows built by the anecic earthworm Lumbricus terrestris in soil and quantified the amount of microplastics that was transported and deposited in L. terrestris burrows. Worms were exposed to soil surface litter treatments containing microplastics (Low Density Polyethylene) for 2 weeks at concentrations of 0%, 7%, 28%, 45% and 60%. The latter representing environmentally realistic concentrations found in hot spot soil locations. There were significantly more burrows found when soil was exposed to the surface treatment composed of 7% microplastics than in all other treatments. The highest amount of organic matter in the walls of the burrows was observed after using the treatments containing 28 and 45% microplastics. The highest microplastic bioturbation efficiency ratio (total microplastics (mg) in burrow walls/initial total surface litter microplastics (mg)) was found using the concentration of 7% microplastics, where L. terrestris introduced 73.5% of the surface microplastics into the burrow walls. The highest burrow wall microplastic content per unit weight of soil (11.8 ± 4.8 g kg-(1)) was found using a concentration of 60% microplastics. L. terrestris was responsible for size-selective downward transport when exposed to concentrations of 7, 28 and 45% microplastics in the surface litter, as the fraction ≤50 μm microplastics in burrow walls increased by 65% compared to this fraction in the original surface litter plastic. We conclude that the high biogenic incorporation rate of the small-fraction microplastics from surface litter into burrow walls causes a risk of leaching through preferential flow into groundwater bodies. Furthermore, this leaching may have implications for the subsequent availability of microplastics to terrestrial organisms or for the transport

  3. Photogrammetric survey of dinosaur skeletons

    Directory of Open Access Journals (Sweden)

    A. Wiedemann

    1999-01-01

    Full Text Available To derive physiological data of dinosaurs, it is necessary to determine the volume and the surface area of this animals. For this purpose, a detailed survey of reconstructed skeletons is required. The skeletons of three dinosaurs in the Museum für Naturkunde in Berlin and two skeletons in the Museum d'Histoire Naturelle in Paris have been surveyed using stereo photogrammetry. Two of the Berlin skeletons were also surveyed with the close range laser scanners of the Institut für Navigation of the Universität Stuttgart. Both data acquisition techniques require a geodetic control network as a geometric reference system. The surveying methods used, together with results of mathematical approaches for the determination of the volume and surface of the animals are presented in this paper. Zur Herleitung physiologischer Daten der Dinosaurier ist es erforderlich, zunächst Volumen und Oberfläche ihres Körpers zu bestimmen. Dazu wurde eine detaillierte Vermessung rekonstruierter Skelette durchgeführt. Die Skelette dreier Saurier im Museum für Naturkunde in Berlin und zweier im Museum d'Histoire Naturelle in Paris wurden stereophotogrammetrisch vermessen. Bei zwei der Berliner Skelette wurden zusätzlich die Laserscanner des Instituts für Navigation der Universität Stuttgart eingesetzt. Beide Datenerfassungstechniken benötigen ein Paßpunktfeld als geometrisches Referenzsystem. Die verwendeten Vermessungsmethoden, die mathematischen Ansätze für die Berechnung von Volumina und Oberflächen und die Ergebnisse werden in diesem Aufsatz vorgestellt. doi:10.1002/mmng.1999.4860020108

  4. All about Dinosaurs. Animal Life for Children. [Videotape].

    Science.gov (United States)

    2000

    Dinosaurs were the rulers of the land 65 million years ago. In this videotape, children learn more about the different kinds of dinosaurs by viewing vivid illustrations and fossil discoveries. Students compare the dinosaurs to their modern kin--snakes, lizards, and crocodiles. Students also listen to different theories to try to answer the big…

  5. The Great Dinosaur Feud: Science against All Odds

    Science.gov (United States)

    Clary, Renee; Wandersee, James; Carpinelli, Amy

    2008-01-01

    In the 19th century, the race to uncover dinosaur fossils and name new dinosaur species inspired two rival scientists, Edward Drinker Cope and Othniel Charles Marsh, to behave in ways that were the antithesis of scientific methods. Subterfuge, theft, and espionage were the ingredients of the Great Dinosaur Feud. Because students often enjoy…

  6. Den narrative tilgang

    DEFF Research Database (Denmark)

    Bo, Inger Glavind

    2016-01-01

    I kapitlet gennemgås en socialkonstruktivistisk forståelse af narrativer. I kapitlet vil jeg gennemgå centrale teoretiske pointer, der samlet set er grundlæggende for en social konstruktivistisk forståelse af narrativer for herved at udfolde forståelsen af den narrative tilgang og desuden...... tydeliggøre, hvordan tilgangen er forbundet med en særlig forståelse af identitetsskabelse. Der er tale om pointer der almindeligvis forbindes med ”små fortællinger” i form af længere identitetsfortællinger og narrative interviews. Kapitlet gennemgår således centrale inspirationskilder og teoretiske pointer...

  7. Velkommen til den posthumane tilstand

    DEFF Research Database (Denmark)

    Wamberg, Jacob

    2015-01-01

    Hvorfor er moderne kunst så insisterende mærkværdig? Fordi den udforsker en posthuman tilstand, som bliver stadig mere påtrængende.......Hvorfor er moderne kunst så insisterende mærkværdig? Fordi den udforsker en posthuman tilstand, som bliver stadig mere påtrængende....

  8. Forord til den danske udgave

    DEFF Research Database (Denmark)

    Egelund, Niels

    2014-01-01

    Forord til den danske udgave af: Leading and managing a differentiated classroom / af Carol Ann Tomlinson og Marcia B. Imbeau......Forord til den danske udgave af: Leading and managing a differentiated classroom / af Carol Ann Tomlinson og Marcia B. Imbeau...

  9. Den medicinal-industrielle logik

    DEFF Research Database (Denmark)

    Børsen, Tom

    2008-01-01

    Et kig på medicinalindustrien og den logik der styrer udviklingen af nye lægemidler. Antagelsen er, at der også eksisterer et medicinalindustrielt kompleks, bestående af ledende industrifolk, læger, forskere og regeringsembedsmænd, der alle har kommercielle interesser i den herskende lægemiddeltæ...

  10. Neue Anforderungen an den Datenschutz

    Science.gov (United States)

    Dix, Alexander

    Eine von der Europäischen Kommission 2003 in Auftrag gegebene Studie hat die rasante technische Entwicklung hin zu "Ambient Intelligence Technologies“ als die größte Herausforderung für den Datenschutz bezeichnet, die sogar größer als die Herausforderung durch den internationalen Terrorismus nach dem 11. September sei.

  11. Stordriftsfordele i den danske banksektor?

    DEFF Research Database (Denmark)

    Kristensen, Troels

    2008-01-01

    Dette er en empirisk undersøgelse af skalaegenskaber (economies of scale) i den danske banksektor baseret på cross-section data. Banksektorens omkostningsfunktion er estimeret vha. en translogomkostningsfunktion og OLS-regression. Ud fra den estimerede omkostningsfunktion er skalaegenskaberne...

  12. Litteratur i den argumentative ret

    DEFF Research Database (Denmark)

    Jørgensen, Stine

    2007-01-01

    Med udgangspunkt i den litterære rett, slik som denne er udviklet af den amerikanske retsfilosof Martha Nussbaum, argumentere de for, at litteraturen er velegnet som en metode til at opnå menneskelig forståelse. Som led i denne problemstillingen behandles følelsenes plads i retsvidenskaben. Endelig...

  13. Origin of tropical American burrowing reptiles by transatlantic rafting

    OpenAIRE

    Vidal, Nicolas; Azvolinsky, Anna; Cruaud, Corinne; Hedges, S Blair

    2007-01-01

    Populations of terrestrial or freshwater taxa that are separated by oceans can be explained by either oceanic dispersal or fragmentation of a previously contiguous land mass. Amphisbaenians, the worm lizards (approx. 165 species), are small squamate reptiles that are uniquely adapted to a burrowing lifestyle and inhabit Africa, South America, Caribbean Islands, North America, Europe and the Middle East. All but a few species are limbless and they rarely leave their subterranean burrows. Given...

  14. Function of Hexagenia (Mayfly) Burrows: Fluid Model Suggests Bacterial Gardening

    Science.gov (United States)

    Traynham, B.; Furbish, D.; Miller, M.; White, D.

    2006-12-01

    Lake and stream bottoms experience an array of physical, chemical, and biological processes that create spatial variations both in the fluid column and in the sediment that provide a physical template for distinct niches. Burrowing insects are major ecological engineers of communities where they structure large areas of the benthic habitat through bioturbation and other activities including respiration, feeding, and defecation. The burrowing mayfly Hexagenia, when present in high densities, has a large impact on food-web dynamics and provides essential ecosystem services within the fluid column and benthic substrate, including sediment mixing, nutrient cycling, and ultimately, energy flow through the freshwater food web. It has long been recognized that particular benthic species are important in linking detrital energy resources to higher trophic levels and for determining how organic matter is processed in freshwater ecosystems; however, the unique contributions made by individual benthic species is largely absent from the literature. Here we present a model that describes the structure and function of a Hexagenia burrow. If testing supports this hypothesis, the model suggests that when high food concentration is available to Hexagenia, there exists a favorable tube length for harvesting bacteria that grow on the burrow walls. The burrow microhabitat created by Hexagenia serves as a case-study in understanding the influence of benthic burrowers on both energy flow through freshwater food webs and nutrient cycling.

  15. Forearm posture and mobility in quadrupedal dinosaurs.

    Directory of Open Access Journals (Sweden)

    Collin S VanBuren

    Full Text Available Quadrupedality evolved four independent times in dinosaurs; however, the constraints associated with these transitions in limb anatomy and function remain poorly understood, in particular the evolution of forearm posture and rotational ability (i.e., active pronation and supination. Results of previous qualitative studies are inconsistent, likely due to an inability to quantitatively assess the likelihood of their conclusions. We attempt to quantify antebrachial posture and mobility using the radius bone because its morphology is distinct between extant sprawled taxa with a limited active pronation ability and parasagittal taxa that have an enhanced ability to actively pronate the manus. We used a sliding semi-landmark, outline-based geometric morphometric approach of the proximal radial head and a measurement of the angle of curvature of the radius in a sample of 189 mammals, 49 dinosaurs, 35 squamates, 16 birds, and 5 crocodilians. Our results of radial head morphology showed that quadrupedal ceratopsians, bipedal non-hadrosaurid ornithopods, and theropods had limited pronation/supination ability, and sauropodomorphs have unique radial head morphology that likely allowed limited rotational ability. However, the curvature of the radius showed that no dinosaurian clade had the ability to cross the radius about the ulna, suggesting parallel antebrachial elements for all quadrupedal dinosaurs. We conclude that the bipedal origins of all quadrupedal dinosaur clades could have allowed for greater disparity in forelimb posture than previously appreciated, and future studies on dinosaur posture should not limit their classifications to the overly simplistic extant dichotomy.

  16. Forearm posture and mobility in quadrupedal dinosaurs.

    Science.gov (United States)

    VanBuren, Collin S; Bonnan, Matthew

    2013-01-01

    Quadrupedality evolved four independent times in dinosaurs; however, the constraints associated with these transitions in limb anatomy and function remain poorly understood, in particular the evolution of forearm posture and rotational ability (i.e., active pronation and supination). Results of previous qualitative studies are inconsistent, likely due to an inability to quantitatively assess the likelihood of their conclusions. We attempt to quantify antebrachial posture and mobility using the radius bone because its morphology is distinct between extant sprawled taxa with a limited active pronation ability and parasagittal taxa that have an enhanced ability to actively pronate the manus. We used a sliding semi-landmark, outline-based geometric morphometric approach of the proximal radial head and a measurement of the angle of curvature of the radius in a sample of 189 mammals, 49 dinosaurs, 35 squamates, 16 birds, and 5 crocodilians. Our results of radial head morphology showed that quadrupedal ceratopsians, bipedal non-hadrosaurid ornithopods, and theropods had limited pronation/supination ability, and sauropodomorphs have unique radial head morphology that likely allowed limited rotational ability. However, the curvature of the radius showed that no dinosaurian clade had the ability to cross the radius about the ulna, suggesting parallel antebrachial elements for all quadrupedal dinosaurs. We conclude that the bipedal origins of all quadrupedal dinosaur clades could have allowed for greater disparity in forelimb posture than previously appreciated, and future studies on dinosaur posture should not limit their classifications to the overly simplistic extant dichotomy.

  17. The evolution of dinosaur tooth enamel microstructure.

    Science.gov (United States)

    Hwang, Sunny H

    2011-02-01

    The evolution of tooth enamel microstructure in both extinct and extant mammalian groups has been extensively documented, but is poorly known in reptiles, including dinosaurs. Previous intensive sampling of dinosaur tooth enamel microstructure revealed that: (1) the three-dimensional arrangement of enamel types and features within a tooth-the schmelzmuster-is most useful in diagnosing dinosaur clades at or around the family level; (2) enamel microstructure complexity is correlated with tooth morphology complexity and not necessarily with phylogenetic position; and (3) there is a large amount of homoplasy within Theropoda but much less within Ornithischia. In this study, the examination of the enamel microstructure of 28 additional dinosaur taxa fills in taxonomic gaps of previous studies and reinforces the aforementioned conclusions. Additionally, these new specimens reveal that within clades such as Sauropodomorpha, Neotheropoda, and Euornithopoda, the more basal taxa have simpler enamel that is a precursor to the more complex enamel of more derived taxa and that schmelzmusters evolve in a stepwise fashion. In the particularly well-sampled clade of Euornithopoda, correlations between the evolution of dental and enamel characters could be drawn. The ancestral schmelzmuster for Genasauria remains ambiguous due to the dearth of basal ornithischian teeth available for study. These new specimens provide new insights into the evolution of tooth enamel microstructure in dinosaurs, emphasizing the importance of thorough sampling within broadly inclusive clades, especially among their more basal members.

  18. Den Sønderjyske Historiekanon

    DEFF Research Database (Denmark)

    2015-01-01

    Den Sønderjyske Historiekanon er et interaktivt læremiddel, hvor elever og andre interesserede kan blive klogere på den sønderjyske historie og debattere, hvilke begivenheder i Sønderjyllands historie der har størst betydning for deres liv i dag. På den måde kan de få en fornemmelse for, hvorfor...... det er væsentligt at forholde sig til fortiden. Den primære målgruppe er unge i folkeskolens ældre klasser og på ungdomsuddannelserne. Den Sønderjyske Historiekanon præsenterer gennem tekst og video 20 forskellige højdepunkter fra den sønderjyske historie. Opretter man en bruger, kan man deltage i...... afstemningsresultat for alle unge sønderjyske brugere, kaldet ”Den Fælles Sønderjyske Historiekanon”. Begge disse kanoner kan sammen med hjemmesidens materiale om historiebevidsthed bruges som udgangspunkt for refleksioner om, i hvilken grad man i dag kan tale om en særlig sønderjysk identitet....

  19. The Use of Computational Fluid Dynamics in Predicting the Tidal Flushing of Animal Burrows

    Science.gov (United States)

    Heron, S. F.; Ridd, P. V.

    2001-04-01

    Numerical hydrodynamic modelling has been used extensively over the last few decades to simulate flow in the ocean, bays and estuaries; however, modelling of much smaller scale phenomena is less common. In this work a commercially available Computational Fluid Dynamics package (FIDAP), normally used for industrial applications, was used to simulate tidally-induced flow in multi-opening animal burrows. U-shaped burrows of varying complexities were modelled to determine the effect of different surface characteristics and burrow geometries on surface water velocities, burrow velocities and burrow flushing times. The turbulent 2D model showed the slope of the surface water was proportional to the square of both the surface and burrow velocities. The effect of placing a root in the surface flow was to reduce the surface water velocity; however, the burrow flow depended upon the root position. For the root location either upstream or downstream of the burrow, the burrow velocity was reduced by 50%. With the root located between the burrow openings the burrow velocity increased by 200%, due to the increase in pressure difference across the burrow openings. A buttress root placed in the flow immediately downstream of the upstream burrow, caused the burrow flushing rate to increase significantly with increasing buttress height. Flushing times for burrows of varying depth were determined computationally by use of a tracer for the burrow water. For a burrow of depth 1·2 m, the flushing times were 5 and 28 min for root location between the burrow openings and downstream of the burrow, respectively. Animal burrows often consist of multiply-connected loops. A second burrow was added to the primary burrow and flushing times were found to be 15 and 38 min, respectively. A burrow system of four connected burrows was modelled which had corresponding flushing times up to 24 and 47 min, respectively. The calculated times are consistent with the hypothesis that a significant flushing

  20. Growth dynamics of Australia's polar dinosaurs.

    Science.gov (United States)

    Woodward, Holly N; Rich, Thomas H; Chinsamy, Anusuya; Vickers-Rich, Patricia

    2011-01-01

    Analysis of bone microstructure in ornithopod and theropod dinosaurs from Victoria, Australia, documents ontogenetic changes, providing insight into the dinosaurs' successful habitation of Cretaceous Antarctic environments. Woven-fibered bone tissue in the smallest specimens indicates rapid growth rates during early ontogeny. Later ontogeny is marked by parallel-fibered tissue, suggesting reduced growth rates approaching skeletal maturity. Bone microstructure similarities between the ornithopods and theropods, including the presence of LAGs in each group, suggest there is no osteohistologic evidence supporting the hypothesis that polar theropods hibernated seasonally. Results instead suggest high-latitude dinosaurs had growth trajectories similar to their lower-latitude relatives and thus, rapid early ontogenetic growth and the cyclical suspensions of growth inherent in the theropod and ornithopod lineages enabled them to successfully exploit polar regions.

  1. Piscivory in the feathered dinosaur Microraptor.

    Science.gov (United States)

    Xing, Lida; Persons, W Scott; Bell, Phil R; Xu, Xing; Zhang, Jianping; Miyashita, Tetsuto; Wang, Fengping; Currie, Philip J

    2013-08-01

    The largest specimen of the four-winged dromaeosaurid dinosaur Microraptor gui includes preserved gut contents. Previous reports of gut contents and considerations of functional morphology have indicated that Microraptor hunted in an arboreal environment. The new specimen demonstrates that this was not strictly the case, and offers unique insights into the ecology of nonavian dinosaurs early in the evolution of flight. The preserved gut contents are composed of teleost fish remains. Several morphological adaptations of Microraptor are identified as consistent with a partially piscivorous diet, including dentition with reduced serrations and forward projecting teeth on the anterior of the dentary. The feeding habits of Microraptor can now be understood better than that of any other carnivorous nonavian dinosaur, and Microraptor appears to have been an opportunistic and generalist feeder, able to exploit the most common prey in both the arboreal and aquatic microhabitats of the Early Cretaceous Jehol ecosystem.

  2. Gideon Mantell and the Discovery of Dinosaurs

    Science.gov (United States)

    Dean, Dennis R.

    1999-01-01

    Gideon Mantell and the Discovery of Dinosaurs is a scholarly yet accessible biography--the first in a generation--of a pioneering dinosaur hunter and scholar. Gideon Mantell discovered the Iguanodon (a famous tale set right in this book) and several other dinosaur species, spent over twenty-five years restoring Iguanodon fossils, and helped establish the idea of an Age of Reptiles that ended with their extinction at the conclusion of the Mesozoic Era. He had significant interaction with such well-known figures as James Parkinson, Georges Cuvier, Charles Lyell, Roderick Murchison, Charles Darwin, and Richard Owen. Dennis Dean, a well-known scholar of geology and the Victorian era, here places Mantell's career in its cultural context, employing original research in archives throughout the world, including the previously unexamined Mantell family papers in New Zealand.

  3. Plumage color patterns of an extinct dinosaur.

    Science.gov (United States)

    Li, Quanguo; Gao, Ke-Qin; Vinther, Jakob; Shawkey, Matthew D; Clarke, Julia A; D'Alba, Liliana; Meng, Qingjin; Briggs, Derek E G; Prum, Richard O

    2010-03-12

    For as long as dinosaurs have been known to exist, there has been speculation about their appearance. Fossil feathers can preserve the morphology of color-imparting melanosomes, which allow color patterns in feathered dinosaurs to be reconstructed. Here, we have mapped feather color patterns in a Late Jurassic basal paravian theropod dinosaur. Quantitative comparisons with melanosome shape and density in extant feathers indicate that the body was gray and dark and the face had rufous speckles. The crown was rufous, and the long limb feathers were white with distal black spangles. The evolution of melanin-based within-feather pigmentation patterns may coincide with that of elongate pennaceous feathers in the common ancestor of Maniraptora, before active powered flight. Feathers may thus have played a role in sexual selection or other communication.

  4. Metabolism of dinosaurs as determined from their growth

    Science.gov (United States)

    Lee, Scott A.

    2015-09-01

    A model based on cellular properties is used to analyze the mass growth curves of 20 dinosaurs. This analysis yields the first measurement of the average cellular metabolism of dinosaurs. The organismal metabolism is also determined. The cellular metabolism of dinosaurs is found to decrease with mass at a slower rate than is observed in extant animals. The organismal metabolism increases with the mass of the dinosaur. These results come from both the Saurischia and Ornithischia branches of Dinosauria, suggesting that the observed metabolic features were common to all dinosaurs. The results from dinosaurs are compared to data from extant placental and marsupial mammals, a monotreme, and altricial and precocial birds, reptiles, and fish. Dinosaurs had cellular and organismal metabolisms in the range observed in extant mesotherms.

  5. Den iscenesatte folkelighed

    Directory of Open Access Journals (Sweden)

    Néstor Garcia Canclini

    1994-09-01

    Full Text Available Hvad er "det folkelige" og hvad er "folkekultur"? Néstor Garcia Canclini har i denne artikel sat sig for at dekonstruere begrebet "det folkelige" og beskrive den måde, forskellige grupper bruger og misbruger begrebet på. Han analyserer tre fremherskende idéer om folkelighed: folkloristernes romantiske idé om det oprindelige, der blev ødelagt af massekulturen, massemediernes popularitetsbegreb og endelig populisternes - både de højre- og venstreorienteredes - iscenesættelse af folkeligheden. Desuden ser han på to marxistiske skolers opfattelse af forholdet mellem de dominerende og undertrykte klasser og forskellige definitioner af folkelig- hed. Ligesom Anamaria Fadul argumenterer Canclini for nødvendigheden af en ny, tværdiciplinær forskning, som opfanger kompleksitet og flerty- digheder i forholdet mellem de undertrykte og dominerende og ser "det folkelige" som en tragisk komedie med modsætninger og flertydighed snarere end en evigt fremadskrivende episk fortælling. Artiklen er en forkortet udgave af kapitel 5 i Canclinis bog fra 1989: "Culturas Hibridas - Estrategias para entrat y salir de la modernidad. Mexico: Grijalbo.

  6. Dinosaurs nesting on a red beach?

    Science.gov (United States)

    Sander, P. Martin; Peitz, Christian; Gallemi, Jaume; Cousin, Rémi

    1998-07-01

    The Upper Cretaceous Basturs locality (Tremp Basin, northern Spain) preserves numerous dinosaur eggs ( Megaloolithus cf. M. mammilare Vianey-Liaud, 1994). The locality was recently studied by Sanz et al. (1995) as well as by us. However, we have to disagree with several conclusions by Sanz et al. and suggest alternative interpretations incorporating data from other localities (Coll de Nargó). The dinosaurs at Basturs did not nest at the beach, nor is there evidence for colonial nesting and territorial behaviour. However, the locality superbly documents nesting site fidelity with an estimated occupation time of over 10 000 years.

  7. Dinosaur Footprint Fossils Discovered in Xinjiang

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Recently,a Chinese-German science fieldwork investigation team,composed of staff from the SinoGerman Paleontology and Geography Joint Lab and the Xinjiang Geological Work Station,announced that they discovered a batch of dinosaur footprint fossils in the dessert 20 kilometers to the east of Shanshan County in the Turpan Basin,Xinjiang Uyghur Autonomous Region.These fossils spread around an area of 100 square meters and scientists believed that these footprints were left behind by carnivore dinosaurs.This major discovery has been published in Global Geology,an English journal published by the NorthEast Asia Geology Center.

  8. Geochemical and mineralogical studies of dinosaur bone from the Morrison Formation at Dinosaur Ridge

    Science.gov (United States)

    Modreski, P.J.

    2001-01-01

    The dinosaur bones first discovered in 1877 in the Upper Jurassic Morrison Formation at Morrison, Colorado were the first major find of dinosaur skeletons in the western U.S. and led to the recognition of four new dinosaur genera (Apatosaurus, Allosaurus, Diplodocus, and Stegosaurus). Eight articles dealing with these bones which appeared as research reports in the annual reports of the Friends of Dinosaur Ridge from 1990-1999 are condensed and summarized with some additional comments. Two of the articles are about the mineralogy and preservation of the bones; two are about the physical description of the bone occurrence; two are about the history of the site, and two are about use of novel instrumental methods (ground-penetrating radar and a directional scintillometer) to search for new bones.

  9. New horned dinosaurs from Utah provide evidence for intracontinental dinosaur endemism.

    Directory of Open Access Journals (Sweden)

    Scott D Sampson

    Full Text Available BACKGROUND: During much of the Late Cretaceous, a shallow, epeiric sea divided North America into eastern and western landmasses. The western landmass, known as Laramidia, although diminutive in size, witnessed a major evolutionary radiation of dinosaurs. Other than hadrosaurs (duck-billed dinosaurs, the most common dinosaurs were ceratopsids (large-bodied horned dinosaurs, currently known only from Laramidia and Asia. Remarkably, previous studies have postulated the occurrence of latitudinally arrayed dinosaur "provinces," or "biomes," on Laramidia. Yet this hypothesis has been challenged on multiple fronts and has remained poorly tested. METHODOLOGY/PRINCIPAL FINDINGS: Here we describe two new, co-occurring ceratopsids from the Upper Cretaceous Kaiparowits Formation of Utah that provide the strongest support to date for the dinosaur provincialism hypothesis. Both pertain to the clade of ceratopsids known as Chasmosaurinae, dramatically increasing representation of this group from the southern portion of the Western Interior Basin of North America. Utahceratops gettyi gen. et sp. nov.-characterized by short, rounded, laterally projecting supraorbital horncores and an elongate frill with a deep median embayment-is recovered as the sister taxon to Pentaceratops sternbergii from the late Campanian of New Mexico. Kosmoceratops richardsoni gen. et sp. nov.-characterized by elongate, laterally projecting supraorbital horncores and a short, broad frill adorned with ten well developed hooks-has the most ornate skull of any known dinosaur and is closely allied to Chasmosaurus irvinensis from the late Campanian of Alberta. CONCLUSIONS/SIGNIFICANCE: Considered in unison, the phylogenetic, stratigraphic, and biogeographic evidence documents distinct, co-occurring chasmosaurine taxa north and south on the diminutive landmass of Laramidia. The famous Triceratops and all other, more nested chasmosaurines are postulated as descendants of forms previously

  10. Events i den globale bykonkurrence

    DEFF Research Database (Denmark)

    Østergaard, Katrine

    2005-01-01

    Paper til ph.d. workshop, d. 9. december 2005. Dette paper beskriver, hvorfor og hvordan events kan bruges som strategi for byplanlægning og byudvikling i den globale bykonkurrence.......Paper til ph.d. workshop, d. 9. december 2005. Dette paper beskriver, hvorfor og hvordan events kan bruges som strategi for byplanlægning og byudvikling i den globale bykonkurrence....

  11. Den Blå Drage

    DEFF Research Database (Denmark)

    Ingerslev, Gitte Holten

    Denne publikation i serien Læselyst tjener tre formål. Den evaluerer læseprojektet Den blå drage i efteråret 2004 på Byskolen i Svendborg ? et projekt ledet af forfatteren Josefine Ottesen. Desuden gøres der rede for nogle af de teorier der støtter og begrunder arbejdsmåde og resultater i projektet...

  12. Den tidslogiske analyse af determinismeproblemet

    DEFF Research Database (Denmark)

    Øhrstrøm, Peter

    2010-01-01

    Artiklen diskuterer den filosofiske tidslogik med særligt henblik på A.N. Priors bidrag hertil. Det logiske determinismeproblem benyttes som gennemgående eksempel. Det vises endvidere, hvordan tidslogikken kan udnyttes til at analysere de logisk mulige positioner i en videnskabelig eller videnska...... videnskabsteoretisk debat. Her bruges den videnskabshistorisk betydende diskussion mellem Charles Darwin og Asa Gray som eksempel....

  13. Burrowing criteria and burrowing mode adjustment in bivalves to varying geoenvironmental conditions in intertidal flats and beaches.

    Directory of Open Access Journals (Sweden)

    Shinji Sassa

    Full Text Available The response of bivalves to their abiotic environment has been widely studied in relation to hydroenvironmental conditions, sediment types and sediment grain sizes. However, the possible role of varying geoenvironmental conditions in their habitats remains poorly understood. Here, we show that the hardness of the surficial intertidal sediments varies by a factor of 20-50 due to suction development and suction-induced void state changes in the essentially saturated states of intertidal flats and beaches. We investigated the response of two species of bivalves, Ruditapes philippinarum and Donax semigranosus, in the laboratory by simulating such prevailing geoenvironmental conditions in the field. The experimental results demonstrate that the bivalve responses depended strongly on the varying geoenvironmental conditions. Notably, both bivalves consistently shifted their burrowing modes, reducing the burrowing angle and burial depth, in response to increasing hardness, to compensate for the excessive energy required for burrowing, as explained by a proposed conceptual model. This burrowing mode adjustment was accompanied by two burrowing criteria below or above which the bivalves accomplished vertical burrowing or failed to burrow, respectively. The suitable and fatal conditions differed markedly with species and shell lengths. The acute sensitivities of the observed bivalve responses to geoenvironmental changes revealed two distinctive mechanisms accounting for the adult-juvenile spatial distributions of Ruditapes philippinarum and the behavioral adaptation to a rapidly changing geoenvironment of Donax semigranosus. The present results may provide a rational basis by which to understand the ensuing, and to predict future, bivalve responses to geoenvironmental changes in intertidal zones.

  14. Use of Artificial Burrows by Burrowing Owls (Athene cunicularia) at the HAMMER Facility on the U.S. Department of Energy Hanford Site

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, Amanda K.; Sackschewsky, Michael R.; Duberstein, Corey A.

    2005-09-30

    In 2003 the U.S. Department of Energy (DOE) constructed an Emergency Vehicle Operations Course (EVOC) at the Hazardous Material Management and Emergency Response Training and Education Center (HAMMER) in the southern portion of the Hanford Site. Preliminary surveys during 2001 identified an active burrowing owl (Athene cunicularia) burrow and three burrowing owls within the proposed development area. Burrowing owls were classified as a federal species of concern, a Washington State ?candidate? species, a Washington Department of Fish and Wildlife priority species, and a Hanford Site Biological Resources Management Plan Level III resource. Therefore, the mitigation action plan for the project included the installation of twenty artificial burrows around EVOC in the spring of 2003. The mitigation plan established a success criterion of five percent annual use of the burrows by owls. In July 2005, a field survey of the EVOC burrow complex was conducted to determine use and demography at each site. Burrow locations were mapped and signs of activity (feces, owl tracks, castings, feathers) were recorded. Out of the twenty burrows, twelve were found to be active. Of the eight inactive burrows three appeared to have been active earlier in the 2005 breeding season. A total of nineteen owls were counted but demography could not be determined. It appears that the EVOC mitigation exceeded burrow use goals during 2005. Continued site monitoring and maintenance, according to mitigation plan guidelines should be conducted as prescribed.

  15. Den litterære blog

    DEFF Research Database (Denmark)

    Serup, Martin Glaz; Kromann, Thomas Hvid

    2012-01-01

    Hvad er en litterær blog og hvordan arbejder den som en aktiv del af den litterære offentlighed.......Hvad er en litterær blog og hvordan arbejder den som en aktiv del af den litterære offentlighed....

  16. Ny bog: Den farvede franske general

    DEFF Research Database (Denmark)

    Østergaard, Uffe

    2013-01-01

    Anmeldelse af: Tom Reiss: 'Den sorte greve. Napoleons rival og den virkelige greve af Monte Cristo', Informations Forlag, 517 s.......Anmeldelse af: Tom Reiss: 'Den sorte greve. Napoleons rival og den virkelige greve af Monte Cristo', Informations Forlag, 517 s....

  17. Fossil Dinosaur Slept Like a Bird

    Institute of Scientific and Technical Information of China (English)

    Michael Hopkin; 王伟

    2004-01-01

    @@ The angst①-ridden Prince Hamlet described death as an eternal② sleep,fearfully wondering what dreams may come during the everlasting slumber③. So perhaps he would have empathized④ with a dinosaur newly unearthed in China: it seems to have been preserved in the act of sleeping.

  18. Scaling in Theropod Dinosaurs: Femoral Bone Dimensions

    Science.gov (United States)

    Lee, Scott A.

    2014-01-01

    Finding topics that inspire students is an important aspect of any physics course. Virtually everyone is fascinated by "Tyrannosaurus rex," and the excitement of the class is palpable when we explore scaling effects in "T. rex" and other bipedal theropod dinosaurs as part of our discussion of mechanics and elasticity. In this…

  19. Plant cover effect on Bolson tortoise (Gopherus flavomarginatus Legler 1959, Testudinidae burrow use

    Directory of Open Access Journals (Sweden)

    Jorge Luis Becerra-López

    2017-03-01

    Full Text Available The Bolson tortoise, Gopherus flavomarginatus, occurs within a restricted geographical area in the Mexican Chihuahuan Desert. We analyzed the variation in surface microhabitat with relation to the burrow occupancy for this tortoise at the Mapimí Biosphere Reserve, Mexico. In summer 2010, we monitored burrow activity (active, inactive, or abandoned and measured environmental factors that might influence the burrow’s occupancy by tortoises (air temperature, relative humidity and substrate temperature, both inside and outside the burrow, and the plant cover around it. Discriminant analysis was used to identify the importance of these variables influencing burrow occupancy. Correlation and linear regression analyses were performed to quantify the relation between environmental factors in the sampled burrows. Results. Sixty-one burrows were identified at the Tortugas locality. The first function’s auto-value analysis indicates that this function explains 97.9% of the variation in burrow activity status; high occupancy scores were associated with low substrate temperature inside the burrow. Plant cover was inversely proportional to substrate temperature inside the burrow. These results suggest the importance the density of plants surrounding the tortoise’s burrow as a key factor influencing the burrow microclimate and occupancy by the tortoises. Conclusions. Gopherus flavomarginatus inhabits burrows, in part, based on microhabitat structure, with plant cover being a main factor influencing burrow occupancy. Our findings indicate that human land use and vegetation management are important for conserving Bolson tortoises, and for understanding habitat conditions necessary for the successful establishment of populations elsewhere.

  20. Mechanics and kinematics of backward burrowing by the polychaete Cirriformia moorei.

    Science.gov (United States)

    Che, James; Dorgan, Kelly M

    2010-12-15

    The polychaete Cirriformia moorei burrows in muddy sediments by fracture, using its hydrostatic skeleton to expand its anterior region and exert force against its burrow wall to extend a crack. Burrowing occurs in four phases: stretching forward into the burrow, extending the crack anteriorly, thickening the burrowing end to amplify stress at the tip of the crack, and bringing the rest of the body forward as a peristaltic wave travels posteriorly. Here, we show that C. moorei is also able to burrow with its posterior end using a similar mechanism of crack propagation and exhibiting the same four phases of burrowing. Worms burrowed backwards with similar speeds and stress intensity factors as forward burrowing, but were thinner and less blunt and did not slip as far away from the crack tip between cycles of burrowing. The anterior end is more muscular and rigid, and differences in body shapes are consistent with having reduce musculature to dilate the posterior segments while burrowing. Backward burrowing provides a unique opportunity to study the effects of morphology on burrowing mechanics within the same species under identical conditions.

  1. [Raman spectra of fossil dinosaurs from different regions].

    Science.gov (United States)

    Yang, Qun; Wang, Yi-lin

    2007-12-01

    Raman microscopic spectra in the higher wave number region were obtained from 7 fossil dinosaurs specimens from different regions. The specimens of fossil dinosaurs are different parts of bone. The Raman spectra of fossil dinosaurs indicate the high similarity among peak positions of different fossil dinosaurs; but important differences exist in the spectral peak figures. In the wave number region of 1000-1800 cm(-1) the Raman spectra of the same bone part fossils from different regions are very similar, example similarities between spectra of Lufeing backbone head and Yua nmou backbone head; Lufeng limb bone and Wuding limb bone. There are relations between the same bone part spectra of different fossil dinosaurs. The characteristic does not relate to regions. Raman spectra of fossil dinosaurs cannot be used to distinguish fossil source, although the part of bone can be used as an indicator to narrow the range of possible geographical origins.

  2. Artificial and Modified Burrows Establishment for the Atlantic Puffin on Petit Manan Island, Maine

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — An attempt to establish a breeding population of Atlantic puffin colony using artificial and modified burrows on Petit Manan Island resulted in 3 of 17 burrows being...

  3. The origin and early evolution of dinosaurs.

    Science.gov (United States)

    Langer, Max C; Ezcurra, Martin D; Bittencourt, Jonathas S; Novas, Fernando E

    2010-02-01

    The oldest unequivocal records of Dinosauria were unearthed from Late Triassic rocks (approximately 230 Ma) accumulated over extensional rift basins in southwestern Pangea. The better known of these are Herrerasaurus ischigualastensis, Pisanosaurus mertii, Eoraptor lunensis, and Panphagia protos from the Ischigualasto Formation, Argentina, and Staurikosaurus pricei and Saturnalia tupiniquim from the Santa Maria Formation, Brazil. No uncontroversial dinosaur body fossils are known from older strata, but the Middle Triassic origin of the lineage may be inferred from both the footprint record and its sister-group relation to Ladinian basal dinosauromorphs. These include the typical Marasuchus lilloensis, more basal forms such as Lagerpeton and Dromomeron, as well as silesaurids: a possibly monophyletic group composed of Mid-Late Triassic forms that may represent immediate sister taxa to dinosaurs. The first phylogenetic definition to fit the current understanding of Dinosauria as a node-based taxon solely composed of mutually exclusive Saurischia and Ornithischia was given as "all descendants of the most recent common ancestor of birds and Triceratops". Recent cladistic analyses of early dinosaurs agree that Pisanosaurus mertii is a basal ornithischian; that Herrerasaurus ischigualastensis and Staurikosaurus pricei belong in a monophyletic Herrerasauridae; that herrerasaurids, Eoraptor lunensis, and Guaibasaurus candelariensis are saurischians; that Saurischia includes two main groups, Sauropodomorpha and Theropoda; and that Saturnalia tupiniquim is a basal member of the sauropodomorph lineage. On the contrary, several aspects of basal dinosaur phylogeny remain controversial, including the position of herrerasaurids, E. lunensis, and G. candelariensis as basal theropods or basal saurischians, and the affinity and/or validity of more fragmentary taxa such as Agnosphitys cromhallensis, Alwalkeria maleriensis, Chindesaurus bryansmalli, Saltopus elginensis, and

  4. A New "Missing Link" in Dinosaur's Evolution Found

    Institute of Scientific and Technical Information of China (English)

    Song J.; Zhao B.

    2002-01-01

    @@ A group of paleontologists from China, the United States and Canada have made new progress in tracking down the process of the evolution of smallsized dinosaurs and the origin of birds through intensive analysis of the fossils of a newly found dinosaur,Sinovenator, a close relative of birds. In a letter published in the Feb.14 issue of Nature, dinosaur expert Dr. Xu Xing at CAS Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) and his coworkers reveal some interesting phenomena in the process of the evolution of dinosaurs towards birds.

  5. Superiority, competition, and opportunism in the evolutionary radiation of dinosaurs.

    Science.gov (United States)

    Brusatte, Stephen L; Benton, Michael J; Ruta, Marcello; Lloyd, Graeme T

    2008-09-12

    The rise and diversification of the dinosaurs in the Late Triassic, from 230 to 200 million years ago, is a classic example of an evolutionary radiation with supposed competitive replacement. A comparison of evolutionary rates and morphological disparity of basal dinosaurs and their chief "competitors," the crurotarsan archosaurs, shows that dinosaurs exhibited lower disparity and an indistinguishable rate of character evolution. The radiation of Triassic archosaurs as a whole is characterized by declining evolutionary rates and increasing disparity, suggesting a decoupling of character evolution from body plan variety. The results strongly suggest that historical contingency, rather than prolonged competition or general "superiority," was the primary factor in the rise of dinosaurs.

  6. The second Jurassic dinosaur rush and the dawn of dinomania.

    Science.gov (United States)

    Brinkman, Paul D

    2010-09-01

    During the second Jurassic dinosaur rush museum paleontologists raced to display the world's first mounted sauropod dinosaur. The American Museum of Natural History triumphed in 1905 when its Brontosaurus debuted before an admiring crowd of wealthy New Yorkers. The Carnegie Museum of Natural History in Pittsburgh, the Field Columbian Museum in Chicago and other institutions were quick to follow with their own sauropod displays. Thereafter, dinomania spread far and wide, and big, showpiece dinosaurs became a museum staple. This brief but intensely competitive period of acquisitiveness fostered important Jurassic dinosaur revisions and crucial innovations in paleontological field and lab techniques.

  7. Der kommer den danske model

    DEFF Research Database (Denmark)

    Lundquist, Lita Sander; Gravier, Magali

    2016-01-01

    Alene en titel som »Humor i EU« er nok til at fremkalde smil og spørgsmål om, hvorvidt det virkelig kan være rigtigt. I den grad forekommer det som en selvmodsigelse, at der skulle findes humor i Europaparlamentet (EP).......Alene en titel som »Humor i EU« er nok til at fremkalde smil og spørgsmål om, hvorvidt det virkelig kan være rigtigt. I den grad forekommer det som en selvmodsigelse, at der skulle findes humor i Europaparlamentet (EP)....

  8. Flensborg den 24. maj 1943

    DEFF Research Database (Denmark)

    Thomsen, Merete Bo

    2014-01-01

    Et bombardement af Flensborg 19. maj 1943 kostede mange ofre på både tysk og dansk side. Artiklen sammenligner det danske mindretals begravelsesceremoni med den nazistiske med særligt vægt på de forskellige indslags signalværdi over for det omgivende samfund.......Et bombardement af Flensborg 19. maj 1943 kostede mange ofre på både tysk og dansk side. Artiklen sammenligner det danske mindretals begravelsesceremoni med den nazistiske med særligt vægt på de forskellige indslags signalværdi over for det omgivende samfund....

  9. Oxygen penetration around burrows and roots in aquatic sediments

    DEFF Research Database (Denmark)

    Meysman, Filip J.R.; Galaktionov, O.S.; Glud, Ronnie N.

    2010-01-01

    Diffusion is the dominant physical mechanism for the transfer of oxygen into fine-grained aquatic sediments. This diffusive uptake occurs at the sediment-water interface, but also at internal interfaces, such as along ventilated burrows or O2 releasing plant roots. Here, we present a systematic...

  10. Incorporation of microplastics from litter into burrows of Lumbricus terrestris

    NARCIS (Netherlands)

    Huerta Lwanga, Esperanza; Gertsen, H.F.; Gooren, H.; Peters, P.; Salanki, T.E.; Ploeg, van der M.; Besseling, E.; Koelmans, A.A.; Geissen, V.

    2017-01-01

    Pollution caused by plastic debris is an urgent environmental problem. Here, we assessed the effects of microplastics in the soil surface litter on the formation and characterization of burrows built by the anecic earthworm Lumbricus terrestris in soil and quantified the amount of microplastics that

  11. Skull ecomorphology of megaherbivorous dinosaurs from the dinosaur park formation (upper campanian) of Alberta, Canada.

    Science.gov (United States)

    Mallon, Jordan C; Anderson, Jason S

    2013-01-01

    Megaherbivorous dinosaur coexistence on the Late Cretaceous island continent of Laramidia has long puzzled researchers, owing to the mystery of how so many large herbivores (6-8 sympatric species, in many instances) could coexist on such a small (4-7 million km(2)) landmass. Various explanations have been put forth, one of which-dietary niche partitioning-forms the focus of this study. Here, we apply traditional morphometric methods to the skulls of megaherbivorous dinosaurs from the Dinosaur Park Formation (upper Campanian) of Alberta to infer the ecomorphology of these animals and to test the niche partitioning hypothesis. We find evidence for niche partitioning not only among contemporaneous ankylosaurs, ceratopsids, and hadrosaurids, but also within these clades at the family and subfamily levels. Consubfamilial ceratopsids and hadrosaurids differ insignificantly in their inferred ecomorphologies, which may explain why they rarely overlap stratigraphically: interspecific competition prevented their coexistence.

  12. Skull ecomorphology of megaherbivorous dinosaurs from the dinosaur park formation (upper campanian of Alberta, Canada.

    Directory of Open Access Journals (Sweden)

    Jordan C Mallon

    Full Text Available Megaherbivorous dinosaur coexistence on the Late Cretaceous island continent of Laramidia has long puzzled researchers, owing to the mystery of how so many large herbivores (6-8 sympatric species, in many instances could coexist on such a small (4-7 million km(2 landmass. Various explanations have been put forth, one of which-dietary niche partitioning-forms the focus of this study. Here, we apply traditional morphometric methods to the skulls of megaherbivorous dinosaurs from the Dinosaur Park Formation (upper Campanian of Alberta to infer the ecomorphology of these animals and to test the niche partitioning hypothesis. We find evidence for niche partitioning not only among contemporaneous ankylosaurs, ceratopsids, and hadrosaurids, but also within these clades at the family and subfamily levels. Consubfamilial ceratopsids and hadrosaurids differ insignificantly in their inferred ecomorphologies, which may explain why they rarely overlap stratigraphically: interspecific competition prevented their coexistence.

  13. Factors affecting detection of burrowing owl nests during standardized surveys

    Science.gov (United States)

    Conway, C.J.; Garcia, V.; Smith, M.D.; Hughes, K.

    2008-01-01

    Identifying causes of declines and evaluating effects of management practices on persistence of local populations of burrowing owls (Athene cunicularia) requires accurate estimates of abundance and population trends. Moreover, regulatory agencies in the United States and Canada typically require surveys to detect nest burrows prior to approving developments or other activities in areas that are potentially suitable for nesting burrowing owls. In general, guidelines on timing of surveys have been lacking and surveys have been conducted at different times of day and in different stages of the nesting cycle. We used logistic regression to evaluate 7 factors that could potentially affect probability of a surveyor detecting a burrowing owl nest. We conducted 1,444 detection trials at 323 burrowing owl nests within 3 study areas in Washington and Wyoming, USA, between February and August 2000-2002. Detection probability was highest during the nestling period and increased with ambient temperature. The other 5 factors that we examined (i.e., study area, time of day, timing within the breeding season, wind speed, % cloud cover) interacted with another factor to influence detection probability. Use of call-broadcast surveys increased detection probability, even during daylight hours when we detected >95% of owls visually. Optimal timing of surveys will vary due to differences in breeding phenology and differences in nesting behavior across populations. Nevertheless, we recommend ???3 surveys per year: one that coincides with the laying and incubation period, another that coincides with the early nestling period, and a third that coincides with the late nestling period. In northern latitudes, surveys can be conducted throughout the day.

  14. Models for the rise of the dinosaurs.

    Science.gov (United States)

    Benton, Michael J; Forth, Jonathan; Langer, Max C

    2014-01-20

    Dinosaurs arose in the early Triassic in the aftermath of the greatest mass extinction ever and became hugely successful in the Mesozoic. Their initial diversification is a classic example of a large-scale macroevolutionary change. Diversifications at such deep-time scales can now be dissected, modelled and tested. New fossils suggest that dinosaurs originated early in the Middle Triassic, during the recovery of life from the devastating Permo-Triassic mass extinction. Improvements in stratigraphic dating and a new suite of morphometric and comparative evolutionary numerical methods now allow a forensic dissection of one of the greatest turnovers in the history of life. Such studies mark a move from the narrative to the analytical in macroevolutionary research, and they allow us to begin to answer the proposal of George Gaylord Simpson, to explore adaptive radiations using numerical methods.

  15. On the probability of dinosaur fleas.

    Science.gov (United States)

    Dittmar, Katharina; Zhu, Qiyun; Hastriter, Michael W; Whiting, Michael F

    2016-01-11

    Recently, a set of publications described flea fossils from Jurassic and Early Cretaceous geological strata in northeastern China, which were suggested to have parasitized feathered dinosaurs, pterosaurs, and early birds or mammals. In support of these fossils being fleas, a recent publication in BMC Evolutionary Biology described the extended abdomen of a female fossil specimen as due to blood feeding.We here comment on these findings, and conclude that the current interpretation of the evolutionary trajectory and ecology of these putative dinosaur fleas is based on appeal to probability, rather than evidence. Hence, their taxonomic positioning as fleas, or stem fleas, as well as their ecological classification as ectoparasites and blood feeders is not supported by currently available data.

  16. Tillid i den finansielle sektor

    DEFF Research Database (Denmark)

    Rimmer, Nina Røhr; Nielsen, Sara Møller; Benediktsdottir, Elisabet

    2014-01-01

    , der er i kommunikation med kunden, eksempelvis at videreudvikle på definerede Touch-Points i CEM og opbyggelsen/vedligeholdelsen af kundeoplysninger i CRM systemer således, at den samlede kvalitet af ydelsen bliver så personlig som mulig, hvilket falder godt i tråd med Spar Nords værdigrundlag om dels...

  17. Udstillingen og den gode historie

    DEFF Research Database (Denmark)

    Dickson, Thomas

    1998-01-01

    Artiklen indledes med: af de mange kommunikaationsformaer der findes er 'udstillingen' blandt de mest levende og realistiske. Udstillingsmediet giver publikum mulighed for at opleve 'the real thing' og ikke bare en eller anden form for todimensionel reproduktion. Men den traditionelle udstilling ...

  18. den og morderen

    DEFF Research Database (Denmark)

    Hansen, Kim Toft

    2014-01-01

    forskellige versioner af Forbrydelsen: DR's oprindelige udgave, AMC's udgave The Killing og David Hewsons roman Forbrydelsen, der er baseret på manuskriptet til DR-serien. Grundfortællingen under disse tre versioner relaterer jeg til H.C. Andersens "Historien om en Moder" og tilskrivningen af mening til døden....

  19. Lower Cretaceous Dinosaur Tracks from Puebla, Mexico

    OpenAIRE

    2012-01-01

    Dinosaur tracks have been identified near San Martín Atexcal, southern Puebla, Mexico, within the sedimentary sequence of the San Juan Raya Formation of Lower Cretaceous (Albian) age. The tracksite, located in the bed of the Magdalena River, reveals six different ichnofossiliferous levels identified within a 9 m thick sedimentary sequence. The inferred environment is that of a tidal (marginal marine) mudflat (Level I). Level I preserves three theropods trackways (?Allosauroidea), additionally...

  20. No sign of decreased burrowing behavior in the genetically depressive flinders rats

    DEFF Research Database (Denmark)

    Baastrup, C. S.; Wegener, Gregers; Finnerup, N. B.

    2012-01-01

    Background: Burrowing is a natural behavior in rats and has been observed in several different strains. Furthermore decreased burrowing behavior has been shown in different rodent disease models like Multiple sclerosis, peripheral nerve injury and knee inflammation when compared with control...... of each drug. Results: The genetically depressive FSL rats did not burrow less than FRL control rats. Treatment with imipramin or citalopram-S did not change the burrowing behavior of the FSL rats. In contrast treatment with imipramin and citalopram-S unexpectedly decreased the burrowing behavior...

  1. Cockroaches probably cleaned up after dinosaurs.

    Science.gov (United States)

    Vršanský, Peter; van de Kamp, Thomas; Azar, Dany; Prokin, Alexander; Vidlička, L'ubomír; Vagovič, Patrik

    2013-01-01

    Dinosaurs undoubtedly produced huge quantities of excrements. But who cleaned up after them? Dung beetles and flies with rapid development were rare during most of the Mesozoic. Candidates for these duties are extinct cockroaches (Blattulidae), whose temporal range is associated with herbivorous dinosaurs. An opportunity to test this hypothesis arises from coprolites to some extent extruded from an immature cockroach preserved in the amber of Lebanon, studied using synchrotron X-ray microtomography. 1.06% of their volume is filled by particles of wood with smooth edges, in which size distribution directly supports their external pre-digestion. Because fungal pre-processing can be excluded based on the presence of large particles (combined with small total amount of wood) and absence of damages on wood, the likely source of wood are herbivore feces. Smaller particles were broken down biochemically in the cockroach hind gut, which indicates that the recent lignin-decomposing termite and cockroach endosymbionts might have been transferred to the cockroach gut upon feeding on dinosaur feces.

  2. Dinosaur Peptides Suggest Mechanisms of Protein Survival

    Energy Technology Data Exchange (ETDEWEB)

    San Antonio, James D.; Schweitzer, Mary H.; Jensen, Shane T.; Kalluri, Raghu; Buckley, Michael; Orgel, Joseph P.R.O. (Harvard-Med); (IIT); (NCSU); (UPENN); (Manchester); (Orthovita)

    2011-09-16

    Eleven collagen peptide sequences recovered from chemical extracts of dinosaur bones were mapped onto molecular models of the vertebrate collagen fibril derived from extant taxa. The dinosaur peptides localized to fibril regions protected by the close packing of collagen molecules, and contained few acidic amino acids. Four peptides mapped to collagen regions crucial for cell-collagen interactions and tissue development. Dinosaur peptides were not represented in more exposed parts of the collagen fibril or regions mediating intermolecular cross-linking. Thus functionally significant regions of collagen fibrils that are physically shielded within the fibril may be preferentially preserved in fossils. These results show empirically that structure-function relationships at the molecular level could contribute to selective preservation in fossilized vertebrate remains across geological time, suggest a 'preservation motif', and bolster current concepts linking collagen structure to biological function. This non-random distribution supports the hypothesis that the peptides are produced by the extinct organisms and suggests a chemical mechanism for survival.

  3. A basal dinosaur from the dawn of the dinosaur era in southwestern Pangaea.

    Science.gov (United States)

    Martinez, Ricardo N; Sereno, Paul C; Alcober, Oscar A; Colombi, Carina E; Renne, Paul R; Montañez, Isabel P; Currie, Brian S

    2011-01-14

    Upper Triassic rocks in northwestern Argentina preserve the most complete record of dinosaurs before their rise to dominance in the Early Jurassic. Here, we describe a previously unidentified basal theropod, reassess its contemporary Eoraptor as a basal sauropodomorph, divide the faunal record of the Ischigualasto Formation with biozones, and bracket the formation with (40)Ar/(39)Ar ages. Some 230 million years ago in the Late Triassic (mid Carnian), the earliest dinosaurs were the dominant terrestrial carnivores and small herbivores in southwestern Pangaea. The extinction of nondinosaurian herbivores is sequential and is not linked to an increase in dinosaurian diversity, which weakens the predominant scenario for dinosaurian ascendancy as opportunistic replacement.

  4. "Teachosaurus" and "Learnoceratops": Dinosaurs as a Motivating Cross-Curricular Theme

    Science.gov (United States)

    Duggan, Denis

    2011-01-01

    The author takes a look into the benefits that dinosaurs may bring to the classroom. He discusses how he used dinosaurs as a cross-curricular theme to improve children's understanding and knowledge of science concepts. To investigate what a child might learn from dinosaurs, he started by comparing the many non-fiction dinosaur books using the…

  5. Dens in dente of maxillary third molar

    Directory of Open Access Journals (Sweden)

    Subramaniam Arun

    2008-01-01

    Full Text Available ′Dens in dente,′ also known as dens invaginatus, is a developmental anomaly resulting from deepening or invagination of the enamel organ into the dental papilla, which begins at the crown and often extends to the root before calcification of the dental tissues. Dens in dente commonly occur in the maxillary lateral incisor. This article reports a case of dens in dente in the maxillary third molar.

  6. Seasonal changes in burrow geometry of the common mole rat (Rodentia: Bathyergidae)

    Science.gov (United States)

    Thomas, H. G.; Scantlebury, M.; Swanepoel, D.; Bateman, P. W.; Bennett, N. C.

    2013-11-01

    Sociality in mole rats has been suggested to have evolved as a response to the widely dispersed food resources and the limited burrowing opportunities that result from sporadic rainfall events. In the most arid regions, individual foraging efficiency is reduced, and energetic constraints increase. In this study, we investigate seasonal differences in burrow architecture of the social Cryptomys hottentotus hottentotus in a mesic region. We describe burrow geometry in response to seasonal weather conditions for two seasons (wet and dry). Interactions occurred between seasons and colony size for the size of the burrow systems, but not the shape of the burrow systems. The fractal dimension values of the burrow systems did not differ between seasons. Thus, the burrow complexity was dependent upon the number of mole rats present in the social group.

  7. "Dinosaurs." Kindergarten. Anchorage School District Elementary Science Program.

    Science.gov (United States)

    Herminghaus, Trisha, Ed.

    This unit contains 15 lessons on dinosaurs for kindergarten children. It provides a materials list, supplementary materials list, use of process skill terminology, unit objectives, vocabulary, six major dinosaurs, and background information. Lessons are: (1) "Webbing"; (2) "Introduction to the Big Six"; (3) "Paleontology…

  8. 36 CFR 7.63 - Dinosaur National Monument.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Dinosaur National Monument. 7.63 Section 7.63 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.63 Dinosaur National Monument. (a)...

  9. Scaling in Theropod Dinosaurs: Femoral Bone Strength and Locomotion II

    Science.gov (United States)

    Lee, Scott

    2015-01-01

    In the second paper of this series, the effect of transverse femoral stresses due to locomotion in theropod dinosaurs of different sizes was examined for the case of an unchanging leg geometry. Students are invariably thrilled to learn about theropod dinosaurs, and this activity applies the concepts of torque and stress to the issue of theropod…

  10. Scaling in Theropod Dinosaurs: Femoral Bone Strength and Locomotion

    Science.gov (United States)

    Lee, Scott

    2015-01-01

    In our first article on scaling in theropod dinosaurs, the longitudinal stress in the leg bones due to supporting the weight of the animal was studied and found not to control the dimensions of the femur. As a continuation of our study of elasticity in dinosaur bones, we now examine the transverse stress in the femur due to locomotion and find…

  11. Dinosaur energetics: setting the bounds on feasible physiologies and ecologies.

    Science.gov (United States)

    Clarke, Andrew

    2013-09-01

    The metabolic status of dinosaurs has long been debated but remains unresolved as no consistent picture has emerged from a range of anatomical and isotopic evidence. Quantitative analysis of dinosaur energetics, based on general principles applicable to all vertebrates, shows that many features of dinosaur lifestyle are compatible with a physiology similar to that of extant lizards, scaled up to dinosaur body masses and temperatures. The analysis suggests that sufficient metabolic scope would have been available to support observed dinosaur growth rates and allow considerable locomotor activity, perhaps even migration. Since at least one dinosaur lineage evolved true endothermy, this study emphasizes there was no single dinosaur physiology. Many small theropods were insulated with feathers and appear to have been partial or full endotherms. Uninsulated small taxa, and all juveniles, presumably would have been ectothermic, with consequent diurnal and seasonal variations in body temperature. In larger taxa, inertial homeothermy would have resulted in warm and stable body temperatures but with a basal metabolism significantly below that of extant mammals or birds of the same size. It would appear that dinosaurs exhibited a range of metabolic levels to match the broad spectrum of ecological niches they occupied.

  12. "Dinosaurs." Kindergarten. Anchorage School District Elementary Science Program.

    Science.gov (United States)

    Herminghaus, Trisha, Ed.

    This unit contains 15 lessons on dinosaurs for kindergarten children. It provides a materials list, supplementary materials list, use of process skill terminology, unit objectives, vocabulary, six major dinosaurs, and background information. Lessons are: (1) "Webbing"; (2) "Introduction to the Big Six"; (3) "Paleontology and Fossils"; (4) "How Big…

  13. den på glas

    DEFF Research Database (Denmark)

    Meyer, Ion

    2008-01-01

    Artiklen beskriver den eneste danske samling af præparerede fostre og børn, og hvorfor den blev fremstillet. Den var en del af Museum Saxtorphianum og artiklen diskuterer hvordan disse fostre blev til præparater. Musealiseringen, overgangen fra medicinske studieobjekter til museumsgenstande med s...

  14. Vi kan bryde den negative kulturelle arv

    DEFF Research Database (Denmark)

    Pecseli, Benedicta

    2014-01-01

    Den ny bekendtgørelse for pædagoguddannelsen fokuserer på brydning af den negative sociale arv, men det som inklusionspædagogikken skal inkludere til, eller den horisont inden for hvilken alle børn skal gives lige livschance/mulighed, er der næsten ingen redegørelse for. Begreber som Kultur og...

  15. The oldest dinosaur? A Middle Triassic dinosauriform from Tanzania.

    Science.gov (United States)

    Nesbitt, Sterling J; Barrett, Paul M; Werning, Sarah; Sidor, Christian A; Charig, Alan J

    2013-02-23

    The rise of dinosaurs was a major event in vertebrate history, but the timing of the origin and early diversification of the group remain poorly constrained. Here, we describe Nyasasaurus parringtoni gen. et sp. nov., which is identified as either the earliest known member of, or the sister-taxon to, Dinosauria. Nyasasaurus possesses a unique combination of dinosaur character states and an elevated growth rate similar to that of definitive early dinosaurs. It demonstrates that the initial dinosaur radiation occurred over a longer timescale than previously thought (possibly 15 Myr earlier), and that dinosaurs and their immediate relatives are better understood as part of a larger Middle Triassic archosauriform radiation. The African provenance of Nyasasaurus supports a southern Pangaean origin for Dinosauria.

  16. 76 FR 7232 - Notice of Inventory Completion: U.S. Department of the Interior, National Park Service, Dinosaur...

    Science.gov (United States)

    2011-02-09

    ... Service, Dinosaur National Monument, Dinosaur, CO AGENCY: National Park Service, Interior. ACTION: Notice. SUMMARY: The U.S. Department of the Interior, National Park Service, Dinosaur National Monument, Dinosaur... culturally affiliated with the human remains may contact Dinosaur National Monument. Disposition of the...

  17. Filmretorik og den internationale politik

    Directory of Open Access Journals (Sweden)

    Astrid Söderbergh Widding

    2005-09-01

    Full Text Available Med baggrund i de seneste års krigs- og terrorhandlinger – Afghanistan, Irak, den 11. september – reflekterer forfatteren over forholdet mellem krig, tilskuer, medier og forestillinger om virkeligheden. Forholdet mellem medier og virkelighed tenderer ifølge forfatteren mod at smelte sammen i en gennemmedieret kultur, hvor fremstillingsformer fra for eksempel film kan anvendes til at formidle faktiske begivenheder. Forfatterens blik på mediekulturen tager afsæt i flere aktuelle udgivelser fra postmodernis- mens centrale filosoffer, blandt andet Jean Baudrillard og Paul Virilio. Denne artikel er dermed samtidig en introduktion til deres refleksioner over terrorhandlingerne den 11. september og deres betydning i det moderne samfund.

  18. Da den moderne jazz kom til Danmark

    DEFF Research Database (Denmark)

    Høyer, Ole Izard; Nielsen, Anders H.U.

    som tog over, deriblandt Erik Moseholm, Bent Axen og Jørn Elniff. Denne bog forklarer, hvordan den moderne jazz kom til Danmark, og hvordan den udviklede det danske jazzmiljø. Den inddrager faktorer som udenlandske musikeres besøg, koncerter og efterfølgende jazzsessions. Hvilken betydning havde disse...... for den danske jazzudvikling? Hvor blev musikken spillet, og hvordan blev den behandlet af medierne og af samfundet? Sammen med beskrivelser af de vigtigste moderne jazzmusikere fra perioden, analyseres og beskrives en række indspilninger af moderne dansk jazz for at undersøge hvornår, og hvilke af de nye...

  19. Den sociale tillid i Danmark

    DEFF Research Database (Denmark)

    Anhøj, Anne Iversen; Kjærsgård, Andreas Pihl

    2013-01-01

    Nærværende artikel har anvendt de hidtil ubenyttede surveypaneldata, der eksisterer i Danmark til at undersøge udviklingen i social tillid på individniveau over tid. Artiklens analyser viser, at social tillid på individniveau i Danmark synes at være meget stabil, når først den er opnået. Herudover...

  20. Predatory behaviour of carnivorous dinosaurs: Ecological interpretations based on tooth marked dinosaur bones and wear patterns of theropod teeth

    DEFF Research Database (Denmark)

    Jacobsen, Aase Roland

    Predation marks on bones are a source on information on the feeding behaviour of the carnivores involved. Although predator damaged bone is common in the fossil record, published reports of such marks on dinosaur bones are rare. Patterns of bone modification by mammalian carnivores overlap patterns...... left by theropod dinosaurs.Differences in tooth morphology can also be correlated with characteristics of the marks left by the teeth. In a study of tooth marks on dinosaur bones from the Dinosaur Park Formation of Alberta, Canada, it was possible to identify the feeding theropods to family, generic...... different taxa and different skeletal elements produced some interesting results. The frequency of tooth marked dinosaur bones is higher than expected. Up to 14 % of the observed hadrosaur bones were predator damaged. The lower incidence of damage in ceratopsian bones can be explained by the fact...

  1. Konsulenten i den anden nat

    DEFF Research Database (Denmark)

    Kirkegaard, Line

    for i sit deres liv og den eksistensmåde, der hermed muliggøres. Med dette ønsker jeg at bidrage til de eksisterende work-life balance teorier. Min vej ind i teorierne er nemlig, at logikken i mit empiriske materiale forekommer så forskelligt fra de traditionelle work-life balance teorier, at disse ikke...... lader sig forene. Jeg foretage derfor en analyse af den eksisterende litteratur, og rejser i den forbindelse en grundlæggende kritik af work-life balance teorierne, for at operere med falske problemstillinger på en måde, så svaret allerede indgår i de spørgsmål, der stilles. Jeg argumenterer således for......, at det problematiske forhold ved work-life balance teorierne allerede skal søges i konstitueringen af deres problematik, hvor arbejde og fritid indgår som to distinkte og kontrasterende sfærer. Ubalance eller problemer søges således altid i relationen her imellem. I forlængelse heraf argumenterer jeg for...

  2. Does petroleum development affect burrowing owl nocturnal space-use?

    Energy Technology Data Exchange (ETDEWEB)

    Scobie, Corey; Wellicome, Troy; Bayne, Erin [Department of Biological Sciences, University of Alberta (Canada)], email: cscobie@ualberta.ca, email: tiw@ualberta.ca, email: bayne@ualberta.ca

    2011-07-01

    Decline all over Canada in the population of burrowing owls, a federally listed endangered species, has raised concerns about the possible influence of petroleum infrastructure development on owl nocturnal space-use while foraging. Roads, wells, pipelines and sound-producing facilities related to petroleum development change the landscape and can influence the owls' mortality risk. For 3 years, 27 breeding adult male burrowing owls with nests close to different petroleum infrastructures were captured and fitted with a miniature GPS datalogger in order to track their nocturnal foraging. Data from these GPS devices were fed into a geographical information system and showed that pipelines and wells did not alter the foraging habits of the owls. Dirt and gravel roads, with little traffic, were preferentially selected by the owls, conceivably because of higher owl mortality risk along paved roads. Sound-producing facilities did not change owls' foraging behaviour, implying that sound may not affect their nocturnal space-use. Traffic data and sound power measurements will be used in further studies in an effort to better understand burrowing owls' nocturnal foraging habits.

  3. Diet of western Burrowing Owls wintering in southern Texas

    Science.gov (United States)

    Littles, C.J.; Williford, D.; Skoruppa, M.K.; Woodin, M.C.; Hickman, G.C.

    2007-01-01

    Winter diets of the western Burrowing Owl (Athene cunicularia hypugaea) are little known. We determined the diet of western Burrowing Owls wintering in southern Texas by analyzing the contents of 182 pellets collected over four winters (1999-2000, 2001-2002, 2002-2003, and 2003-2004) in three habitat types (agricultural, mainland grassland, and barrier island). Remains of a total of 7476 prey items were recovered, 98% of which were arthropods. Gryllidae (crickets) formed the largest component (50%) of the prey, followed by lepidopteran larvae (13%), beetles (8%), spiders (7%), and earwigs (6%). Although vertebrates, primarily small mammals and birds, represented only 2% of prey items by number, they represented most (71%) of the biomass. Northern pygmy mice (Baiomys taylori) and fulvous harvest mice (Reithrodontomys fulveccens) were the two most frequently consumed vertebrate species. In all habitats, arthropods, especially orthopterans, were the primary prey item by number, whereas vertebrates, primarily small mammals, were the most important by biomass. Greater consumption of arthropods by Burrowing Owls in agricultural areas may be a factor contributing to owl use of these highly altered environments. ?? 2007 The Raptor Research Foundation, Inc.

  4. Origin of tropical American burrowing reptiles by transatlantic rafting.

    Science.gov (United States)

    Vidal, Nicolas; Azvolinsky, Anna; Cruaud, Corinne; Hedges, S Blair

    2008-02-23

    Populations of terrestrial or freshwater taxa that are separated by oceans can be explained by either oceanic dispersal or fragmentation of a previously contiguous land mass. Amphisbaenians, the worm lizards (approx. 165 species), are small squamate reptiles that are uniquely adapted to a burrowing lifestyle and inhabit Africa, South America, Caribbean Islands, North America, Europe and the Middle East. All but a few species are limbless and they rarely leave their subterranean burrows. Given their peculiar habits, the distribution of amphisbaenians has been assumed to be primarily the result of two land-mass fragmentation events: the split of the supercontinent Pangaea starting 200 Myr ago, separating species on the northern land mass (Laurasia) from those on the southern land mass (Gondwana), and the split of South America from Africa 100 Myr ago. Here we show with molecular evidence that oceanic dispersal-on floating islands-played a more prominent role, and that amphisbaenians crossed the Atlantic Ocean in the Eocene (40 Myr ago) resulting in a tropical American radiation representing one-half of all known amphisbaenian species. Until now, only four or five transatlantic dispersal events were known in terrestrial vertebrates. Significantly, this is the first such dispersal event to involve a group that burrows, an unexpected lifestyle for an oceanic disperser.

  5. Rodent burrows in late Pleistocene paleosols at Korean Palaeolithic sites and their implications for paleoclimate changes

    Science.gov (United States)

    Lim, H.; Park, S.; Lee, J.; Lee, Y.

    2013-12-01

    Rodent burrows are commonly found at many Paleolithic archaeological sites in Korea. They are nearly straight in horizontal view and gently inclined in lateral view. Burrow diameters are mostly 7 - 10cm, and burrow length may reach a few meters. Vertical penetration depths are generally about 1 m from the surface, and the thickness of the burrow-bearing layer is about 1-2 m. Although no remains (bones, teeth, claws, and coprolites) were found within burrows, they are interpreted to have been produced by rodent-like mammals (probably ground squirrels) based on the size and architecture. According to the previous study, the age of these burrows was constrained to be between ca. 40,000 and 25,000 yr BP by tephrochronology, radiocarbon and optically stimulated luminescence dating results (Lim et al., 2007). However, little is known about the reason why these burrows have disappeared after late Pleistocene time. For this question, two explanations can be considered: extinction or migration. Since same kinds of burrows are still found in the high-latitude regions, such as Mongolia and North America, the possibility of extinction can be ruled out. Therefore, migration seems to be the most likely explanation. Our results show that the destruction of habitat caused by climate change during this period is the main reason for the northward migration of burrowing animals. This study suggests that rodent burrows found in the late Pleistocene paleosols can provide useful information on paleoclimate and paleoenvironmental changes.

  6. Nest site characteristics and nesting success of the Western Burrowing Owl in the eastern Mojave Desert

    Science.gov (United States)

    Longshore, Kathleen M.; Crowe, Dorothy E.

    2013-01-01

    We evaluated nest site selection at two spatial scales (microsite, territory) and reproductive success of Western Burrowing Owls (Athene cunicularia hypugaea) at three spatial scales (microsite, territory, landscape) in the eastern Mojave Desert. We used binary logistic regression within an information-theoretic approach to assess factors influencing nest site choice and nesting success. Microsite-scale variables favored by owls included burrows excavated by desert tortoise (Gopherus agassizii), burrows with a large mound of excavated soil at the entrance, and a greater number of satellite burrows within 5 m of the nest burrow. At the territory scale, owls preferred patches with greater cover of creosote bush (Larrea tridentata) within 50 m of the nest burrow. An interaction between the presence or absence of a calcic soil horizon layer over the top of the burrow (microsite) and the number of burrows within 50 m (territory) influenced nest site choice. Nesting success was influenced by a greater number of burrows within 5 m of the nest burrow. Total cool season precipitation was a predictor of nesting success at the landscape scale. Conservation strategies can rely on management of habitat for favored and productive nesting sites for this declining species.

  7. Determination of the burrow shapes of Cardisoma guanhumi on Vieques, Puerto Rico

    Directory of Open Access Journals (Sweden)

    Shannon Sample

    2016-02-01

    Full Text Available Objective: To determine the burrow morphology of Cardisoma guanhumi and to determine if a battery-powered fiber optic camera could be used to investigate these burrows. Methods: A portable fiber optic camera was used to investigate 116 active burrows. All burrows were categorized according to shape. The diameter of each burrow was also recorded and biomass calculations were completed at each study site. Results: Analysis showed that different study sites were more likely to have particular burrow shapes than expected. Three main types of burrows were classified as horizontal slide, short and shallow, and inverted-S. A Pearson Chi-square analysis revealed that burrow shape was not equally distributed across study sites (χ2 = 61.05, df = 18, P < 0.000 1. Biomass calculations showed that different sized animals inhabited different study sites (ANOVA; df = 7, MS = 158.3, F = 13.9, P < 0.000 1. The fiber optic camera was useful in determining burrow morphology and occupancy non-destructively. Conclusions: As the locations of juvenile individuals of this species are poorly known, and the species is both ecologically and economically important where it occurs, a greater understanding of burrow morphology and size segregation may help agencies be responsible for managing this natural resource to do so effectively.

  8. Variation of Sediment Properties among the Radial Profiles of Fiddler Crab Burrows in Mangrove Ecosystem

    Directory of Open Access Journals (Sweden)

    Mohammad Mokhtari

    2016-01-01

    Full Text Available Fiddler crabs burrow creates oxic-anoxic interfaces on the burrow walls. Accordingly burrow walls represent the transitions site between oxic and anoxic condition where the sediment properties varied significantly across it. In this study the burrows of three species of fiddler crabs including Uca rosea, Uca forcipata and Uca pardussumieri were sampled at three depth layers. Sediment properties of burrow walls including; temperature, redox potential, pH, density, porosity, water content, organic content, chlorophyll content and solid phase iron pools were measured to determine the magnitude of burrow effects on mangrove sediments. The results indicated that U. paradussumieri effectively reduced the sediment porosity of surrounding sediments down to 45%. Oxidized layer was more extended around U. paradussumieri burrows. Burrow walls of U. forcipata and U. paradussumieri contain higher water content than ambient sediment and burrows of U. rosea efficiently decreased the organic content of sediment. The PCA biplots indicated that the burrow walls of the all three species of fiddler crabs at 3 and 8 cm depth were correlated with oxidized iron. Ambient sediments of U. forcipata habitat were correlated with reduced iron and organic content. At 20 cm depth, burrow walls of U. paradussumieri were highly correlated with water content, while ambient sediment was correlated with reduced iron. The results of this study revealed that the thickness of oxidized layer varied according to sediment depth and burrow volume. Consequently the burrow effect varied significantly among different species of fiddler crabs as results of different habitat characteristics, sediment types and crab size.

  9. Avian-like breathing mechanics in maniraptoran dinosaurs.

    Science.gov (United States)

    Codd, Jonathan R; Manning, Phillip L; Norell, Mark A; Perry, Steven F

    2008-01-22

    In 1868 Thomas Huxley first proposed that dinosaurs were the direct ancestors of birds and subsequent analyses have identified a suite of 'avian' characteristics in theropod dinosaurs. Ossified uncinate processes are found in most species of extant birds and also occur in extinct non-avian maniraptoran dinosaurs. Their presence in these dinosaurs represents another morphological character linking them to Aves, and further supports the presence of an avian-like air-sac respiratory system in theropod dinosaurs, prior to the evolution of flight. Here we report a phylogenetic analysis of the presence of uncinate processes in Aves and non-avian maniraptoran dinosaurs indicating that these were homologous structures. Furthermore, recent work on Canada geese has demonstrated that uncinate processes are integral to the mechanics of avian ventilation, facilitating both inspiration and expiration. In extant birds, uncinate processes function to increase the mechanical advantage for movements of the ribs and sternum during respiration. Our study presents a mechanism whereby uncinate processes, in conjunction with lateral and ventral movements of the sternum and gastral basket, affected avian-like breathing mechanics in extinct non-avian maniraptoran dinosaurs.

  10. A palaeoequatorial ornithischian and new constraints on early dinosaur diversification.

    Science.gov (United States)

    Barrett, Paul M; Butler, Richard J; Mundil, Roland; Scheyer, Torsten M; Irmis, Randall B; Sánchez-Villagra, Marcelo R

    2014-09-22

    Current characterizations of early dinosaur evolution are incomplete: existing palaeobiological and phylogenetic scenarios are based on a fossil record dominated by saurischians and the implications of the early ornithischian record are often overlooked. Moreover, the timings of deep phylogenetic divergences within Dinosauria are poorly constrained owing to the absence of a rigorous chronostratigraphical framework for key Late Triassic-Early Jurassic localities. A new dinosaur from the earliest Jurassic of the Venezuelan Andes is the first basal ornithischian recovered from terrestrial deposits directly associated with a precise radioisotopic date and the first-named dinosaur from northern South America. It expands the early palaeogeographical range of Ornithischia to palaeoequatorial regions, an area sometimes thought to be devoid of early dinosaur taxa, and offers insights into early dinosaur growth rates, the evolution of sociality and the rapid tempo of the global dinosaur radiation following the end-Triassic mass extinction, helping to underscore the importance of the ornithischian record in broad-scale discussions of early dinosaur history.

  11. Nonplantigrade Foot Posture: A Constraint on Dinosaur Body Size.

    Directory of Open Access Journals (Sweden)

    Tai Kubo

    Full Text Available Dinosaurs had functionally digitigrade or sub-unguligrade foot postures. With their immediate ancestors, dinosaurs were the only terrestrial nonplantigrades during the Mesozoic. Extant terrestrial mammals have different optimal body sizes according to their foot posture (plantigrade, digitigrade, and unguligrade, yet the relationship of nonplantigrade foot posture with dinosaur body size has never been investigated, even though the body size of dinosaurs has been studied intensively. According to a large dataset presented in this study, the body sizes of all nonplantigrades (including nonvolant dinosaurs, nonvolant terrestrial birds, extant mammals, and extinct Nearctic mammals are above 500 g, except for macroscelid mammals (i.e., elephant shrew, a few alvarezsauroid dinosaurs, and nondinosaur ornithodirans (i.e., the immediate ancestors of dinosaurs. When nonplantigrade tetrapods evolved from plantigrade ancestors, lineages with nonplantigrade foot posture exhibited a steady increase in body size following Cope's rule. In contrast, contemporaneous plantigrade lineages exhibited no trend in body size evolution and were largely constrained to small body sizes. This evolutionary pattern of body size specific to foot posture occurred repeatedly during both the Mesozoic and the Cenozoic eras. Although disturbed by the end-Cretaceous extinction, species of mid to large body size have predominantly been nonplantigrade animals from the Jurassic until the present; conversely, species with small body size have been exclusively composed of plantigrades in the nonvolant terrestrial tetrapod fauna.

  12. Nonplantigrade Foot Posture: A Constraint on Dinosaur Body Size.

    Science.gov (United States)

    Kubo, Tai; Kubo, Mugino O

    2016-01-01

    Dinosaurs had functionally digitigrade or sub-unguligrade foot postures. With their immediate ancestors, dinosaurs were the only terrestrial nonplantigrades during the Mesozoic. Extant terrestrial mammals have different optimal body sizes according to their foot posture (plantigrade, digitigrade, and unguligrade), yet the relationship of nonplantigrade foot posture with dinosaur body size has never been investigated, even though the body size of dinosaurs has been studied intensively. According to a large dataset presented in this study, the body sizes of all nonplantigrades (including nonvolant dinosaurs, nonvolant terrestrial birds, extant mammals, and extinct Nearctic mammals) are above 500 g, except for macroscelid mammals (i.e., elephant shrew), a few alvarezsauroid dinosaurs, and nondinosaur ornithodirans (i.e., the immediate ancestors of dinosaurs). When nonplantigrade tetrapods evolved from plantigrade ancestors, lineages with nonplantigrade foot posture exhibited a steady increase in body size following Cope's rule. In contrast, contemporaneous plantigrade lineages exhibited no trend in body size evolution and were largely constrained to small body sizes. This evolutionary pattern of body size specific to foot posture occurred repeatedly during both the Mesozoic and the Cenozoic eras. Although disturbed by the end-Cretaceous extinction, species of mid to large body size have predominantly been nonplantigrade animals from the Jurassic until the present; conversely, species with small body size have been exclusively composed of plantigrades in the nonvolant terrestrial tetrapod fauna.

  13. The Temptations of the Dinosaur Theory

    OpenAIRE

    Ola Larsmo

    2008-01-01

    Does the book have a future? Ola Larsmo firmly discards the common theory that a new medium makes its predecessor obsolete, terming it ‘the temptations of the dinosaur theory’. This has never happened, he argues. The radio did not replace the newspaper, the television did not replace the radio and the cinema, and so on. There always remains a form of coexistence when the new medium can do something in addition to the previous medium; he terms this ‘x plus 1’. Ola Larsmo concludes that the boo...

  14. Burrow casts from the Lystrosaurus-Procolophon Assemblage-zone, Karoo Sequence, South Africa

    Directory of Open Access Journals (Sweden)

    G.H. Groenewald

    1991-09-01

    Full Text Available Five types of burrow casts from the Lystrosaurus- Procolophon Assemblage-zone (Palingkloof Member and Katberg Formation, Triassic, Karoo sequence. South Africa are associated with casts of desiccation cracks and red mudstone. Vertebrate remains of Lystrosaurus sp. and Procolophon sp. indicate that these animals probably made the burrows during the Triassic. It is possible that burrowing was an adaptive advantage during periods of severe and unfavourable climatic conditions. Similar burrow casts were found in the Dicynodon-Theriognathus Assemblage-zone, suggesting a burrowing habit for fauna represented in this zone. In structure, the burrow casts resemble those of Scoyenia, Thalassinoides, Histioderma, Gyrolithes and Planolites reported from Germany, France, Asia, Ireland, Spain and the United States of America.

  15. Water pumping and analysis of flow in burrowing zoobenthos - a short overview

    DEFF Research Database (Denmark)

    Riisgård, Hans Ulrik; Larsen, Poul Scheel

    2005-01-01

    Burrowing animals maintain contact with the water above the sediment by pumping water through a tube system and therefore measurements of water pumping rate of burrowing animals is of crucial importance for the study of many processes both within and above the sea floor. This review deals...... with the measuring of water pumping and the analysis of flow generated by burrowing deposit- and filter-feeding zoobenthos in order to determine the type of pump and mechanisms involved, flow rate, pump pressure, and pumping power. The practical use of fluid mechanical principles is examined, and it is stressed...... that not only the pump pressure that a burrowing animal can apply is of interest for assessing the energy cost of pumping, but also the distribution of excess pressure along its burrow is of importance for assessing the seepage flow of oxygen-rich water into the sediment surrounding the burrow because...

  16. The taphonomy of dinosaurs from the Upper Jurassic of Tendaguru (Tanzania based on field sketches of the German tendaguru expedition (1909–1913

    Directory of Open Access Journals (Sweden)

    W.-D. Heinrich

    1999-01-01

    Full Text Available Tendaguru is one of the most important dinosaur localities in Africa. The Tendaguru Beds have produced a diverse Late Jurassic (Kimmeridgian to Tithonian dinosaur assemblage, including sauropods (Brachiosaurus, Barosaurus, Dicraeosaurus, Janenschia, theropods (e.g., Elaphrosaurus, Ceratosaurus, Allosaurus, and ornithischians (Kentrosaurus, Dryosaurus. Contrary to the well studied skeletal anatomy of the Tendaguru dinosaurs, the available taphonomic information is rather limited, and a generally accepted taphonomic model has not yet been established. Assessment of unpublished excavation sketches by the German Tendaguru expedition (1909–1913 document bone assemblages of sauropod and ornithischian dinosaurs from the Middle Saurian Bed, Upper Saurian Bed, and the Transitional Sands above the Trigonia smeei Bed, and shed some light on the taphonomy of the Tendaguru dinosaurs. Stages of disarticulation range from incomplete skeletons to solitary bones, and strongly argue for carcass decay and post-mortem transport prior to burial. The sauropod bone accumulations are dominated by adult individuals, and juveniles are rare or missing. The occurrence of bones in different superimposed dinosaur-bearing horizons indicates that skeletal remains were accumulated over a long time span during the Late Jurassic, and the majority of the bone accumulations are probably attritional. These accumulations are likely to have resulted from long-term bone imput due to normal mortality events caused by starvation, seasonal drought, disease, old age and weakness. The depositional environment of the Middle and Upper Saurian Bed was mainly limnic to brackish in origin, while the palaeoenvironment of the Transitional Sands was marginal marine. Tendaguru zählt zu den bedeutendsten Dinosaurier-Lagerstätten Afrikas. Aus den Tendaguru-Schichten sind zahlreiche Skelettreste von Sauropoden (Brachiosaurus, Barosaurus, Dicraeosaurus, Janenschia, Theropoden (z.B. Elaphrosaurus

  17. Dinosaur or Phoenix: Nuclear Bombers in the 21st Century

    Science.gov (United States)

    2010-04-12

    REPORT DATE 02-04-10 2. REPORT TYPE Master’s Thesis 3. DATES COVERED 31-07-09 to 16-06-10 4. TITLE AND SUBTITLE Dinosaur or Phoenix: Nuclear...WARFIGHTING SCHOOL DINOSAUR OR PHOENIX: NUCLEAR BOMBERS IN THE 21ST CENTURY by John W. Morehead Colonel, United States Air Force A paper...can argue Secretary Gates’ decision to halt development of a follow-on bomber indicates the DOD views nuclear bombers as dinosaurs no longer needed as

  18. Were sauropod dinosaurs responsible for the warm Mesozoic climate?

    Institute of Scientific and Technical Information of China (English)

    A.J.(Tom); van; Loon

    2012-01-01

    It was recently postulated that methane production by the giant Mesozoic sauropod dinosaurs was larger than the present-day release of this greenhouse gas by nature and man-induced activities jointly, thus contributing to the warm Mesozoic climate. This conclusion was reached by correct calculations, but these calculations were based on unrealistic assumptions:the researchers who postulated this dinosaur-induced warm climate did take into account neither the biomass production required for the sauropods’ food, nor the constraints for the habitats in which the dinosaurs lived, thus neglecting the palaeogeographic conditions. This underlines the importance of palaeogeography for a good understanding of the Earth’s geological history.

  19. Limb swinging in elephants and giraffes and implications for the reconstruction of limb movements and speed estimates in large dinosaurs

    Directory of Open Access Journals (Sweden)

    A. Christian

    1999-01-01

    Full Text Available Speeds of walking dinosaurs that left fossil trackways have been estimated using the stride length times natural pendulum frequency of the limbs. In a detailed analysis of limb movements in walking Asian elephants and giraffes, however, distinct differences between actual limb movements and the predicted limb movements using only gravity as driving force were observed. Additionally, stride frequency was highly variable. Swing time was fairly constant, but especially at high walking speeds, much shorter than half the natural pendulum period. An analysis of hip and shoulder movements during walking showed that limb swinging was influenced by accelerations of hip and shoulder joints especially at high walking speeds. These results suggest an economical fast walking mechanism that could have been utilised by large dinosaurs to increase maximum speeds of locomotion. These findings throw new light on the dynamics of large vertebrates and can be used to improve speed estimates in large dinosaurs. Geschwindigkeiten gehender Dinosaurier, die fossile Fährten hinterlassen haben, wurden als Produkt aus Schrittlänge und natürlicher Pendelfrequenz der Beine abgeschätzt. Eine detaillierte Analyse der Beinbewegungen von gehenden Asiatischen Elefanten und Giraffen offenbarte allerdings klare Unterschiede zwischen den tatsächlichen Extremitätenbewegungen und den Bewegungen, die zu erwarten wären, wenn die Gravitation die einzige treibende Kraft darstellte. Zudem erwies sich die Schrittfrequenz als hochgradig variabel. Die Schwingzeit der Gliedmaßen war recht konstant, aber besonders bei hohen Gehgeschwindigkeiten viel kürzer als die halbe natürliche Pendelperiode der Extremitäten. Eine Analyse der Bewegungen der Hüft- und Schultergelenke während des Gehens zeigte, daß das Schwingen der Gliedmaßen durch Beschleunigungen dieser Gelenke beeinflußt wurde, insbesondere bei hohen Gehgeschwindigkeiten. Die Resultate legen einen ökonomischen Mechanismus

  20. Burrowing by Sailfin Catfish (Pterygoplichthys sp.): A Potential Cause of Erosion in Disturbed Environments

    Science.gov (United States)

    2014-03-01

    great variation in burrow densities, both within habitats and among different habitats. Burrow density is highly correlated to the amount of silt in...which may have constrained variation in fish abundance. Lastly, sailfin catfish may be predisposed to burrow in areas already prone to moderate...Size structure, reproductive phenology , and sex ratio of an exotic armored catfish (liposarcus multiradiatus) in the Kaoping River of southern

  1. Determinants of between-year burrow re-occupation in a colony of the European bee-eater Merops apiaster.

    Science.gov (United States)

    Brust, Vera; Bastian, Hans-Valentin; Bastian, Anita; Schmoll, Tim

    2015-08-01

    Re-occupation of existing nesting burrows in the European bee-eater Merops apiaster has only rarely - and if so mostly anecdotically - been documented in the literature record, although such behavior would substantially save time and energy. In this study, we quantify burrow re-occupation in a German colony over a period of eleven years and identify ecological variables determining reuse probability. Of 179 recorded broods, 54% took place in a reused burrow and the overall probability that one of 75 individually recognized burrows would be reused in a given subsequent year was estimated as 26.4%. This indicates that between-year burrow reuse is a common behavior in the study colony which contrasts with findings from studies in other colonies. Furthermore, burrow re-occupation probability declined highly significantly with increasing age of the breeding wall. Statistical separation of within- and between-burrow effects of the age of the breeding wall revealed that a decline in re-occupation probability with individual burrow age was responsible for this and not a selective disappearance of burrows with high re-occupation probability over time. Limited duty cycles of individual burrows may be caused by accumulating detritus or decreasing stability with increasing burrow age. Alternatively, burrow fidelity may presuppose pair fidelity which may also explain the observed restricted burrow reuse duty cycles. A consequent next step would be to extend our within-colony approach to other colonies and compare the ecological circumstances under which bee-eaters reuse breeding burrows.

  2. Fossilized excreta associated to dinosaurs in Brazil

    Science.gov (United States)

    Souto, P. R. F.; Fernandes, M. A.

    2015-01-01

    This work provides an updated register of the main occurrences of fossilized excreta (coprolites and urolites) associated with dinosaurs found in the Brazil. The goal is to provide a relevant guide to the interpretation of the environment in the context of Gondwana. In four geographic areas, the excreta are recovered from Cretaceous sedimentary deposits in outcrops of the Bauru and São Luis basins and the Upper Jurassic aeolian deposits of the Parana Basin in the state of São Paulo. The coprolites were analyzed by X-ray diffraction and X-ray fluorescence methods. The results of these analyses reveal compositions that differ from the surrounding matrix, indicating a partial substitution of the organic material due to the feeding habits of the producers. Additionally, we describe the urolite excavations in epirelief and hyporelief, the result of gravitational flow the impact from urine jets on sand. These are associated with ornithopod and theropod dinosaur footprints preserved in the aeolian flagstones of the Botucatu Formation, Parana Basin.

  3. Determination of the burrow shapes of Cardisoma guanhumi on Vieques, Puerto Rico

    Institute of Scientific and Technical Information of China (English)

    Shannon Sample; MarcAlbrecht

    2016-01-01

    Objective: To determine the burrow morphology of Cardisoma guanhumi and to determine if a battery-powered fiber optic camera could be used to investigate these burrows. Methods: A portable fiber optic camera was used to investigate 116 active burrows. All burrows were categorized according to shape. The diameter of each burrow was also recorded and biomass calculations were completed at each study site. Results: Analysis showed that different study sites were more likely to have particular burrow shapes than expected. Three main types of burrows were classified as horizontal slide, short and shallow, and inverted-S. A Pearson Chi-square analysis revealed that burrow shape was not equally distributed across study sites (χ2 = 61.05, df = 18, P Conclusions: As the locations of juvenile individuals of this species are poorly known, and the species is both ecologically and economically important where it occurs, a greater understanding of burrow morphology and size segregation may help agencies be responsible for managing this natural resource to do so effectively.

  4. Berlusconi og den moderne fyrste

    DEFF Research Database (Denmark)

    Sørensen, Gert

    Da Berlusconi dannede sin første regering tilbage i 1994, gav han indtryk af at repræsentere noget tiltrængt nyt, efter den gamle korruptionsramte politiske klasse havde måttet trække sig. Dette billede har ændret sig markant siden, men alligevel blev han valgt igen i 2001, hvor han dannede den...... anden Berlusconi-regering. Ved valget i 2006 var det lige ved at ske igen. Hvad har fået så mange italienere til at støtte Berlusconi? Og hvordan har han formået at fastholde denne støtte? Det er bl.a. disse spørgsmål, bogen prøver at give et svar på. Der er ikke tale om en traditionel biografi om...... Berlusconi. Interessen samler sig om Berlusconi som katalysator for nogle grundlæggende forandringer i italienernes politiske adfærd. Bogen skal ses som en slags tilstandsrapport over en aktuel tidsepoke med rødder tilbage i det Italien, der opstod i 1945 efter fascismens endelige sammenbrud. Bogens første...

  5. Spatial Vegetation Data for Dinosaur National Monument Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This polygon feature class represents vegetation communities mapped at Dinosaur National Monument. The polygons were delineated following guidelines set by the...

  6. Large Mesozoic Mammals Found to Feed on Young Dinosaurs

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ Mammals in the Mesozoic era (280 million to 65 million years ago)are commonly pictured as tiny shrew-like creatures that were mainly insectivorous, probably nocturnal and lived in the shadow of the dinosaurs.

  7. Brief review of dinosaur studies and perspectives in Brazil

    Directory of Open Access Journals (Sweden)

    ALEXANDER W. A. KELLNER

    2000-12-01

    Full Text Available Dinosaur research is developing at very high rates around the world resulting in several new discoveries that are improving our understanding of this terrestrial reptilian clade. Except for the last couple years, the studies of Brazilian dinosaurs have not followed this expansive trend, despite the high potential of several dinosaur localities. So far there are only eight described taxa, four in the last year, representing theropod, sauropod, and one possible prosauropod taxa. Except for footprints, there are no records of ornithischian dinosaurs in the country what is at least partially explainable by the lack of continuous vertebrate fossil collecting program in the country. More funding is necessary to improve the research activities in this field.

  8. Incubation times of dinosaur eggs via embryonic metabolism

    Science.gov (United States)

    Lee, Scott A.

    2016-08-01

    The incubation times for the eggs of 21 dinosaurs are determined from an estimate of their embyronic metabolic rate and the mass of the hatchlings via a mass growth model based on conservation of energy. Embryos in extant birds and crocodiles are studied in order to determine the best model for embryonic metabolism and growth. These results are used to develop a theoretical model that predicts the incubation times of an egg. This model is applied to dinosaur eggs and provides a unique window into dinosaur reproduction. The dinosaurs studied come from both Saurischia and Ornithischia. The incubation times vary from about 28 days for Archaeopteryx lithographica to about 76 days for Alamosaurus sanjuanensis.

  9. Response to Comments on "Evidence for mesothermy in dinosaurs".

    Science.gov (United States)

    Grady, John M; Enquist, Brian J; Dettweiler-Robinson, Eva; Wright, Natalie A; Smith, Felisa A

    2015-05-29

    D'Emic and Myhrvold raise a number of statistical and methodological issues with our recent analysis of dinosaur growth and energetics. However, their critiques and suggested improvements lack biological and statistical justification.

  10. A new carnivorous dinosaur from the Late Jurassic Solnhofen archipelago.

    Science.gov (United States)

    Göhlich, Ursula B; Chiappe, Luis M

    2006-03-16

    Small Late Jurassic theropod dinosaurs are rare worldwide. In Europe these carnivorous dinosaurs are represented primarily by only two skeletons of Compsognathus, neither of which is well preserved. Here we describe a small new theropod dinosaur from the Late Jurassic period of Schamhaupten in southern Germany. Being exquisitely preserved and complete from the snout to the distal third of the tail, the new fossil is the best-preserved predatory, non-avian dinosaur in Europe. It possesses a suite of characters that support its identification as a basal coelurosaur. A cladistic analysis indicates that the new taxon is closer to maniraptorans than to tyrannosauroids, grouping it with taxa often considered to be compsognathids. Large portions of integument are preserved along its tail. The absence of feathers or feather-like structures in a fossil phylogenetically nested within feathered theropods indicates that the evolution of these integumentary structures might be more complex than previously thought.

  11. Die grossen Physiker und ihre Entdeckungen von den fallenden Körpern zu den Quarks

    CERN Document Server

    Segrè, Emilio

    1998-01-01

    Von Galileo Galilei bis zu Richard Feynman und Murray Gell-Mann - von den fallenden Körpern zu den Quarks: Der Physiknobelpreisträger Emilio Segre hat seine ganz persönliche Geschichte der Physik geschrieben. Er erzählt von den großen Gestalten und deren wichtigen Entdeckungen mit großer Anschaulichkeit und Lebendigkeit.

  12. Melanosome evolution indicates a key physiological shift within feathered dinosaurs.

    Science.gov (United States)

    Li, Quanguo; Clarke, Julia A; Gao, Ke-Qin; Zhou, Chang-Fu; Meng, Qingjin; Li, Daliang; D'Alba, Liliana; Shawkey, Matthew D

    2014-03-20

    Inference of colour patterning in extinct dinosaurs has been based on the relationship between the morphology of melanin-containing organelles (melanosomes) and colour in extant bird feathers. When this relationship evolved relative to the origin of feathers and other novel integumentary structures, such as hair and filamentous body covering in extinct archosaurs, has not been evaluated. Here we sample melanosomes from the integument of 181 extant amniote taxa and 13 lizard, turtle, dinosaur and pterosaur fossils from the Upper-Jurassic and Lower-Cretaceous of China. We find that in the lineage leading to birds, the observed increase in the diversity of melanosome morphologies appears abruptly, near the origin of pinnate feathers in maniraptoran dinosaurs. Similarly, mammals show an increased diversity of melanosome form compared to all ectothermic amniotes. In these two clades, mammals and maniraptoran dinosaurs including birds, melanosome form and colour are linked and colour reconstruction may be possible. By contrast, melanosomes in lizard, turtle and crocodilian skin, as well as the archosaurian filamentous body coverings (dinosaur 'protofeathers' and pterosaur 'pycnofibres'), show a limited diversity of form that is uncorrelated with colour in extant taxa. These patterns may be explained by convergent changes in the key melanocortin system of mammals and birds, which is known to affect pleiotropically both melanin-based colouration and energetic processes such as metabolic rate in vertebrates, and may therefore support a significant physiological shift in maniraptoran dinosaurs.

  13. Dinosaur: A Refined Open-Source Peptide MS Feature Detector.

    Science.gov (United States)

    Teleman, Johan; Chawade, Aakash; Sandin, Marianne; Levander, Fredrik; Malmström, Johan

    2016-07-01

    In bottom-up mass spectrometry (MS)-based proteomics, peptide isotopic and chromatographic traces (features) are frequently used for label-free quantification in data-dependent acquisition MS but can also be used for the improved identification of chimeric spectra or sample complexity characterization. Feature detection is difficult because of the high complexity of MS proteomics data from biological samples, which frequently causes features to intermingle. In addition, existing feature detection algorithms commonly suffer from compatibility issues, long computation times, or poor performance on high-resolution data. Because of these limitations, we developed a new tool, Dinosaur, with increased speed and versatility. Dinosaur has the functionality to sample algorithm computations through quality-control plots, which we call a plot trail. From the evaluation of this plot trail, we introduce several algorithmic improvements to further improve the robustness and performance of Dinosaur, with the detection of features for 98% of MS/MS identifications in a benchmark data set, and no other algorithm tested in this study passed 96% feature detection. We finally used Dinosaur to reimplement a published workflow for peptide identification in chimeric spectra, increasing chimeric identification from 26% to 32% over the standard workflow. Dinosaur is operating-system-independent and is freely available as open source on https://github.com/fickludd/dinosaur .

  14. Mesozoic dinosaurs from Brazil and their biogeographic implications.

    Science.gov (United States)

    Bittencourt, Jonathas S; Langer, Max C

    2011-03-01

    The record of dinosaur body-fossils in the Brazilian Mesozoic is restricted to the Triassic of Rio Grande do Sul and Cretaceous of various parts of the country. This includes 21 named species, two of which were regarded as nomina dubia, and 19 consensually assigned to Dinosauria. Additional eight supraspecific taxa have been identified based on fragmentary specimens and numerous dinosaur footprints known in Brazil. In fact, most Brazilian specimens related to dinosaurs are composed of isolated teeth and vertebrae. Despite the increase of fieldwork during the last decade, there are still no dinosaur body-fossils of Jurassic age and the evidence of ornithischians in Brazil is very limited. Dinosaur faunas from this country are generally correlated with those from other parts of Gondwana throughout the Mesozoic. During the Late Triassic, there is a close correspondence to Argentina and other south-Pangaea areas. Mid-Cretaceous faunas of northeastern Brazil resemble those of coeval deposits of North Africa and Argentina. Southern hemisphere spinosaurids are restricted to Africa and Brazil, whereas abelisaurids are still unknown in the Early Cretaceous of the latter. Late Cretaceous dinosaur assemblages of south-central Brazil are endemic only to genus or, more conspicuously, to species level, sharing closely related taxa with Argentina, Madagascar, Indo-Pakistan and, to a lesser degree, continental Africa.

  15. Jagten på den kloge globaliseringsstrategi

    DEFF Research Database (Denmark)

    Mehlsen, Camilla

    2004-01-01

    Den kloge globaliseringsstrategi har fået et navn: Livslang læring. Men er strategien klog, når den fører til et polariseret arbejdsmarked? Og hvem skal betale for at dygtiggøre folk gennem hele livet? Asterisk har talt med professor Andy Green fra University of London. Udgivelsesdato: December...

  16. Den lange vej mod 9. april

    DEFF Research Database (Denmark)

    Clemmesen, Michael Hesselholt

    resultat af en pludselig indskydelse, men den logiske kulmination af årtiers udvikling, hvor Tysklands flåde febrilsk havde søgt veje til at yde et effektivt bidrag til sejren. Også den britiske minering af norsk farvand, der blev gennemført samtidig med at de tyske transporter nærmede sig norske kystbyer...

  17. koncernbegrebet og tilbudspligtens indtræden

    DEFF Research Database (Denmark)

    Clausen, Nis Jul; sørensen, karsten engsig

    2010-01-01

      Med den nye selskabslov og de hertil knyttede ændringer i værdipapirhandelslovens regler om tilbudspligt har man fastholdt ønsket om parallelitet mellem det selskabsretlige koncernbegreb og kriterierne for tilbudspligtens indtræden. Det drøftes, om koncernbegrebet reelt er overført til tilbudsp...

  18. Lederens rolle i den innovative praksis

    DEFF Research Database (Denmark)

    Voxted, Søren; Kristensen, Catharina Juul

    Rapporten er afrapportering af forskningsprojektet 'Lederens rolle i den innovative praksis'. Gennem 12 måneder fulgte de tre forfattere ledere syv ledere forskellige steder i den offentlige sektor for at se, hvordan de gennem innovation håndtere de forandringskrav deres respektive organisationer...

  19. Den filosofiske præstation

    DEFF Research Database (Denmark)

    Skytte Gørtz, Kim Erik

    Bogen gør op med forestillingen om, at filosoffen er uanvendelig i erhvervslivet. Den udfolder en erhvervsfilosofi og inddrager filosoffer som Kant, Hegel, Kierkegaard, Nietzsche, Heidegger og Deleuze......Bogen gør op med forestillingen om, at filosoffen er uanvendelig i erhvervslivet. Den udfolder en erhvervsfilosofi og inddrager filosoffer som Kant, Hegel, Kierkegaard, Nietzsche, Heidegger og Deleuze...

  20. Normer, holdninger og den individualistiske fejlslutning

    DEFF Research Database (Denmark)

    Harder, Peter

    2012-01-01

    Normer er blevet manet ud af lingvistikken i to omgange inden for de sidste hundrede år: Første gang i forbindelse med den strukturalistiske revolution og anden gang i forbindelse med den postmoderne udvikling i variationslingvistikken. Begge gange er normer blevet anskuet som modsætningen til...

  1. Luftstaub über den Meeren

    DEFF Research Database (Denmark)

    Kacunko, Slavko; Kacunko, Sabine; Gorbushina, Ana

    2013-01-01

    Staub umgibt uns überall und alles wird auch irgendwann zu Staub - ob wir wollen oder nicht. Staub nicht nur zu bekämpfen, sondern zu untersuchen, bildet den Ausgangspunkt zahlreicher Forschungen in den Natur-, Ingenieur- und Kulturwissenschaften. Der vorliegende Band verbindet solche Beiträge au...

  2. Den barokke lov i Kafkas "Processen"

    DEFF Research Database (Denmark)

    Simonsen, Karen-Margrethe

    2011-01-01

    Artiklen diskuterer barokke aspekter af loven hos Kafka, idet den inddrager erkendelser fra den historiske barok, blandt andet dobbeltheden af labyrintisk ornamentik og vertikal magt, og inddrager diskussioner af hhv. Gilles Deleuzes, Jacques Derridas og Tzvetan Todorovs læsninger af Kafka....

  3. Den positive psykologis videnskabsteori og metode

    DEFF Research Database (Denmark)

    Andersen, Frans Ørsted; Vogel, Jenny

    2010-01-01

    På basis af interview med professor Michael Eid fra Freie Universität i Berlin gives en introduktion til emnet, Den positive psykologis videnskabsteori og metode......På basis af interview med professor Michael Eid fra Freie Universität i Berlin gives en introduktion til emnet, Den positive psykologis videnskabsteori og metode...

  4. Semiaquatic adaptations in a giant predatory dinosaur.

    Science.gov (United States)

    Ibrahim, Nizar; Sereno, Paul C; Dal Sasso, Cristiano; Maganuco, Simone; Fabbri, Matteo; Martill, David M; Zouhri, Samir; Myhrvold, Nathan; Iurino, Dawid A

    2014-09-26

    We describe adaptations for a semiaquatic lifestyle in the dinosaur Spinosaurus aegyptiacus. These adaptations include retraction of the fleshy nostrils to a position near the mid-region of the skull and an elongate neck and trunk that shift the center of body mass anterior to the knee joint. Unlike terrestrial theropods, the pelvic girdle is downsized, the hindlimbs are short, and all of the limb bones are solid without an open medullary cavity, for buoyancy control in water. The short, robust femur with hypertrophied flexor attachment and the low, flat-bottomed pedal claws are consistent with aquatic foot-propelled locomotion. Surface striations and bone microstructure suggest that the dorsal "sail" may have been enveloped in skin that functioned primarily for display on land and in water.

  5. The Temptations of the Dinosaur Theory

    Directory of Open Access Journals (Sweden)

    Ola Larsmo

    2008-09-01

    Full Text Available Does the book have a future? Ola Larsmo firmly discards the common theory that a new medium makes its predecessor obsolete, terming it ‘the temptations of the dinosaur theory’. This has never happened, he argues. The radio did not replace the newspaper, the television did not replace the radio and the cinema, and so on. There always remains a form of coexistence when the new medium can do something in addition to the previous medium; he terms this ‘x plus 1’. Ola Larsmo concludes that the book in its present form will be with us for many years to come, despite of, and as well as, the tremendous growth of digital information.

  6. Scientists Drill for Clues to Dinosaur Extinction

    Institute of Scientific and Technical Information of China (English)

    张一

    2001-01-01

    @@ [选注者言:20世纪70年代,墨西哥的Yucatan半岛的石油勘探发现了著名的Chicxulub大坑.直到20世纪90年代,科学家才认定,此大坑是由6千5百万年的一颗小行星撞击地球而形成,这次撞击导致地球上的恐龙灭绝.现在,科学家拟再次对此大坑作一番发掘研究,旨在:to determine once andfor all(一劳永逸的;彻底地)whatled to the global extinction(消灭)of the dinosaurs(恐龙)millions of years ago.

  7. Burrow ventilation and associated porewater irrigation by the polychaete Marenzelleria viridis

    DEFF Research Database (Denmark)

    Quintana, Cintia Organo; Hansen, Tanja; Delefosse, Matthieu;

    2011-01-01

    Burrow ventilation of benthic infauna generates water currents that irrigate the interstices of the sediments surrounding the burrow walls. Such activities have associated effects on biogeochemical processes affecting ultimately important ecosystem processes. In this study, the ventilation and ir...

  8. The vibrational signals that male fiddler crabs ( Uca lactea) use to attract females into their burrows

    Science.gov (United States)

    Takeshita, Fumio; Murai, Minoru

    2016-06-01

    In some fiddler crab species, males emit vibrations from their burrows to mate-searching females after they have attracted a female to the burrow entrance using a waving display. Although the vibrations are considered acoustic signals to induce mating, it has not been demonstrated whether the vibrations attract the females into the burrow and, consequently, influence females' mating decisions. We investigated the structures and patterns of the vibrations using a dummy female and demonstrated experimentally a female preference for male vibrations in Uca lactea in the field. The acoustic signals consisted of repetitions of pulses. The dominant frequency of the pulses decreased with male carapace width. The pulse length decreased slightly with an increasing number of vibrational repetitions, and the pulse interval increased with increasing repetitions. These factors imply that the vibrations convey information on male characteristics, such as body size and stamina. In the experiment on female mate choice, the females significantly preferred males with higher pulse repetition rates when they were positioned at the entrance of the burrow, indicating that the females use the male vibrational signals to decide whether to enter the burrow. However, females showed no preference for the vibrations once they were inside a burrow, i.e., whether they decided to copulate, suggesting that the vibrations do not independently affect a female's final decision of mate choice. The vibrations inside the burrow might influence a female's decision by interaction with other male traits such as the burrow structure.

  9. Development of earthworm burrow systems and the influence of earthworms on soil hydrology.

    NARCIS (Netherlands)

    Ligthart, T.N.

    1996-01-01

    Inoculation of earthworms can help to restore or ameliorate land qualities. Earthworms create burrows and alter the structure of the soil matrix, which influence the water infiltration, drainage, water retention and the aeration of the soil. The way and rate of the development of earthworm burrow sy

  10. Irrigation patterns in permeable sediments induced by burrow ventilation: a case study of Arenicola marina

    NARCIS (Netherlands)

    Meysman, F.J.R.; Galaktionov, O.; Middelburg, J.J.

    2005-01-01

    In sandy sediments, a strong connection exists between the physics of flow and the ecology of burrow-ventilating macrofauna. We developed a general modelling procedure that quantifies this link involving 3 steps. (1) Burrow-ventilating organisms can be described as mechanical pumps. (2) The pumping

  11. Water pumping and analysis of flow in burrowing zoobenthos - a short overview

    DEFF Research Database (Denmark)

    Riisgård, H. U.; Larsen, Poul Scheel

    2002-01-01

    Measurement of water pumping rates of burrowing animals is of crucial importance for the study of many processes both within and above the sea floor. This short review deals with water pumping and analysis of flow, including available techniques and bio-fluid mechanical theory, in burrowing deposit...

  12. Den kulturelle dimension af virksomhedens internationalisering

    DEFF Research Database (Denmark)

    Langhoff, Tine

    1994-01-01

    at udnytte muligheder i foranderlige og kulturelt set heterogene omgivelser, så de succe kan påvirke og tilpasse sig disse? (2): Hvorledes forsøger virksomheder at håndtere kulturel heterogenitet på deres eksportmarkeder? Undersøgelsen identificerer tre dimensioner i virksomheders strategifastlæggelse, der......Artiklen omhandler den kulturelle dimensions indvirkning på virksomhedens internationalisering og diskuterer mulige internationalisieringsstrategier for virksomheder, der konfronteres med kulturforskelle. Med udgangspunkt i en kritik af den hidtidige forskning på området, hvor det såkaldte psykiske...... er herved, at den kulturelle dimension påvirker virksomheden og dens fortsatte udvikling. En empirisk analyse i den danske fødevarebranche afdækker virksomheders interkulturelle kompetence ved hjælp af to spørgsmål: (1) Hvorledes formår virksomheder med begrænsede ressourcer til deres disposition...

  13. Scientists Drill for Clues to Dinosaur Extinction

    Institute of Scientific and Technical Information of China (English)

    张一

    2001-01-01

    20世纪70年代,墨西哥的Yucatan半岛的石油勘探发现了著名的Chicxulub大坑。直到20世纪90年代,科学家才认定,此大坑是由6千5百万年的一颗小行星撞击地球而形成,这次撞击导致地球上的恐龙灭绝。现在,科学家拟再次对此大坑作一番发掘研究,旨在:to determine once andfor all(一劳永逸的;彻底地)what led to the global extinction(消灭)of the dinosaurs(恐龙)millions of years ago。 本文为读者描绘了当年地球遭受此灭顶之灾时的可怕情景: Millions of years before humans even existed,a huge meteorite(陨星)measuring about 6 miles across and weighing perhaps billions of tons crashed intothe planet in a ball of fire,shrouding the Earth in a dense cloud of dust that blocked out sunlight and sent temperatures plummeting(垂直落下). 文中有一句话颇能引起读者的共鸣: It’s a 100 million-year event—they don’t occur that often,thank God. 文中的一个成语的使用却值得商榷: …hoping to determine once and for all(一劳永逸的;彻底地)what led to theglobal extinction(消灭)of the dinosaurs(恐龙)millions of years ago.在科学探索的道路上,once and for all也许只是一种良好

  14. River bank burrowing by invasive crayfish: Spatial distribution, biophysical controls and biogeomorphic significance.

    Science.gov (United States)

    Faller, Matej; Harvey, Gemma L; Henshaw, Alexander J; Bertoldi, Walter; Bruno, Maria Cristina; England, Judy

    2016-11-01

    Invasive species generate significant global environmental and economic costs and represent a particularly potent threat to freshwater systems. The biogeomorphic impacts of invasive aquatic and riparian species on river processes and landforms remain largely unquantified, but have the potential to generate significant sediment management issues within invaded catchments. Several species of invasive (non-native) crayfish are known to burrow into river banks and visual evidence of river bank damage is generating public concern and media attention. Despite this, there is a paucity of understanding of burrow distribution, biophysical controls and the potential significance of this problem beyond a small number of local studies at heavily impacted sites. This paper presents the first multi-catchment analysis of this phenomenon, combining existing data on biophysical river properties and invasive crayfish observations with purpose-designed field surveys across 103 river reaches to derive key trends. Crayfish burrows were observed on the majority of reaches, but burrowing tended to be patchy in spatial distribution, concentrated in a small proportion (<10%) of the length of rivers surveyed. Burrow distribution was better explained by local bank biophysical properties than by reach-scale properties, and burrowed banks were more likely to be characterised by cohesive bank material, steeper bank profiles with large areas of bare bank face, often on outer bend locations. Burrow excavation alone has delivered a considerable amount of sediment to invaded river systems in the surveyed sites (3tkm(-1) impacted bank) and this represents a minimum contribution and certainly an underestimate of the absolute yield (submerged burrows were not recorded). Furthermore, burrowing was associated with bank profiles that were either actively eroding or exposed to fluvial action and/or mass failure processes, providing the first quantitative evidence that invasive crayfish may cause or

  15. Landform and surface attributes for prediction of rodent burrows in the Western Usambara Mountains, Tanzania.

    Science.gov (United States)

    Meliyo, Joel L; Massawe, Boniface H J; Msanya, Balthazar M; Kimaro, Didas N; Hieronimo, Proches; Mulungu, Loth S; Kihupi, Nganga I; Deckers, Jozef A; Gulinck, Hubert; Leirs, Herwig

    2014-07-01

    Previous studies suggest that rodent burrows, a proxy for rodent population are important for predicting plague risk areas. However, studies that link landform, surface attributes and rodent burrows in the Western Usambara Mountains in Tanzania are scanty. Therefore, this study was conducted in plague endemic area of the Western Usambara Mountains in northern, Tanzania, to explore the relationship between rodent burrows, and landform and surface attributes. The study was carried out in three areas corresponding to high (Lokome), medium (Lukozi) and low.(Mwangoi) frequency of reported plague cases. Data were collected from 117, 200 and 170 observation sites for Lokome, Lukozi and Mwangoi, respectively using 100 m x 200 m quadrats. Remote sensing and field surveys were used to collect data on landform and surface attributes. Rodent burrows were surveyed and quantified by counting the number of burrows in 20m x 20m grids demarcated on the main 100m x 200m quadrats. The collected data were analysed in R software using boosted regression trees (BRT) technique. Rodent burrows were found at an elevation of above 1600m in the high and medium plague frequency landscapes. No burrows were found in the low plague frequency landscape situated below 1500m. BRT analysis shows a significant relationship between landform characteristics and rodent burrows in both high and medium plague frequency landscapes. Overall, elevation and hillshade are the most important determinants of rodent burrow distribution in the studied landscapes. It is concluded that in high altitudes, specific landform attributes (hill-shade, slope, elevation) and vegetation cover- favour rodent burrowing.

  16. DinoViz: Exploring the History and Nature of Science through the Progression of Dinosaur Visualization

    Science.gov (United States)

    Clary, Renee; Wandersee, James

    2011-01-01

    Dinosaurs in the middle school classroom can be exciting. These extinct reptiles are both an exotic subject and familiar to our students. Because students are inherently interested, dinosaurs can serve as an effective portal for the integration of biology, geology, ecology, and the history and nature of science. The field of dinosaur study is…

  17. Fra dinosaur til fugl - autentisk undervisning

    DEFF Research Database (Denmark)

    Lindow, Bent Erik Kramer; Achiam, Marianne; Simony, Leonora

    2014-01-01

    Undervisning med fokus på hands-on metoder, hvor elevernes resultater er baseret på deres egne aktive undersøgelser, har længe været sat højt indenfor den naturfaglige pædagogik. Men kommer eleverne frem til de samme argumenter og konklusioner som forskerne, når de arbejder med de samme effekter?...

  18. Spilled oil and infaunal activity - Modification of burrowing behavior and redistribution of oil

    Science.gov (United States)

    Clifton, H.E.; Kvenvolden, K.A.; Rapp, J.B.

    1984-01-01

    A series of experiments in Willapa Bay, Washington, indicates the degree to which the presence of spilled oil modifies the burrowing behavior of infauna and the extent to which the animals redistribute oil into intertidal sediment. Small amounts of North Slope crude oil introduced at low tide directly into burrow openings (mostly made by the crustacean Callianassa) resulted in a limited and temporary reduction in the number of burrow openings. In contrast, a layer of oil-saturated sand 1 cm thick buried about 5 cm below the sediment surface sharply reduced the number of burrow openings. After a year, the few new burrows penetrated only the margins of the experimental plot, and bioturbation below the buried oil-saturated sand layer declined dramatically. The experiments suggest that small amounts of oil temporarily stranded by tides in themselves have no long-range effect on burrowing behavior. The fauna, however, are capable of introducing measurable amounts of oil into the subsurface, where it is retained long after the rest of the stranded oil had washed away. A buried layer of oil-saturated sand greatly reduces infaunal activity; the oil presents an effective barrier that can persist for years. The oil incorporated into the sediment from burrow openings showed evidence of degradation after 7 months. In contrast the layer of buried oil remained essentially undergraded after a period of two years, even though oil in lower concentrations above the layer was degraded after a period of one year. This variation in degree of degradation of the buried oil, as well as the heterogeneity of oil distribution wherever the oil has been incorporated from the surface, emphasises the importance of careful sampling in any attempt to locate or monitor the presence of spilled oil in the substrate.In a series of experiments in Willapa Bay, Washington, small amounts of North Slope crude oil introduced at low tide directly into burrow openings resulted in a limited and temporary

  19. Self-burrowing seeds: drag reduction in granular media

    Science.gov (United States)

    Jung, Wonjong; Choi, Sung Mok; Kim, Wonjung; Kim, Ho-Young

    2014-11-01

    We present the results of a combined experimental and theoretical investigation of drag reduction of self-burrowing seeds in granular media. In response to environmental changes in humidity, the awn (a tail-like appendage of seed) of Pelargonium carnosum exhibits coiling-uncoiling deformation which induces the thrust and rotary motions of the head of the seed against the surface of the soil. Using various sizes of glass beads that mimic the granular soil, we measure the thrust forces required for the seed of Pelargonium carnosum to penetrate into granular media with and without rotation. Our quantitative measurements show that the rotation of the seed remarkably reduces the granular drag as compared to the drag against the non-spinning seed. This leads us to conclude that the hygroscopically active awns of Pelargonium carnosum enables its seed to dig into the relatively coarse granular soils.

  20. On Bijective Variants of the Burrows-Wheeler Transform

    CERN Document Server

    Kufleitner, Manfred

    2009-01-01

    The sort transform (ST) is a modification of the Burrows-Wheeler transform (BWT). Both transformations map an arbitrary word of length n to a pair consisting of a word of length n and an index between 1 and n. The BWT sorts all rotation conjugates of the input word, whereas the ST of order k only uses the first k letters for sorting all such conjugates. If two conjugates start with the same prefix of length k, then the indices of the rotations are used for tie-breaking. Both transforms output the sequence of the last letters of the sorted list and the index of the input within the sorted list. In this paper, we discuss a bijective variant of the BWT (due to Scott), proving its correctness and relations to other results due to Gessel and Reutenauer (1993) and Crochemore, Desarmenien, and Perrin (2005). Further, we present a novel bijective variant of the ST.

  1. Mountain building triggered late cretaceous North American megaherbivore dinosaur radiation.

    Directory of Open Access Journals (Sweden)

    Terry A Gates

    Full Text Available Prior studies of Mesozoic biodiversity document a diversity peak for dinosaur species in the Campanian stage of the Late Cretaceous, yet have failed to provide explicit causal mechanisms. We provide evidence that a marked increase in North American dinosaur biodiversity can be attributed to dynamic orogenic episodes within the Western Interior Basin (WIB. Detailed fossil occurrences document an association between the shift from Sevier-style, latitudinally arrayed basins to smaller Laramide-style, longitudinally arrayed basins and a well substantiated decreased geographic range/increased taxonomic diversity of megaherbivorous dinosaur species. Dispersal-vicariance analysis demonstrates that the nearly identical biogeographic histories of the megaherbivorous dinosaur clades Ceratopsidae and Hadrosauridae are attributable to rapid diversification events within restricted basins and that isolation events are contemporaneous with known tectonic activity in the region. SymmeTREE analysis indicates that megaherbivorous dinosaur clades exhibited significant variation in diversification rates throughout the Late Cretaceous. Phylogenetic divergence estimates of fossil clades offer a new lower boundary on Laramide surficial deformation that precedes estimates based on sedimentological data alone.

  2. Diachronism between extinction time of terrestrial and marine dinosaurs

    Science.gov (United States)

    Hansen, H. J.

    1988-01-01

    The dinosaur eggs of southern France occur in continental, fine-grained red-beds, rich in carbonate. The last eggs in the region occur in the magnetic polarity interval 30 normal. Estimates of the accumulation rate of these sediments on the basis of the magneto-stratigraphy leads to placement of the time of disappearance of the dinosaurs in this region of 200,000 to 400,000 years earlier than the Cretaceous-Tertiary boundary. In the Red Deer Valley, Canada, estimates of average accumulation rate lead to a time of disappearance of the dinosaurs of 135,000 to 157,000 years earlier than the Cretaceous-Tertiary boundary. In the central part of Poland, in the Nasilow Quarry, the paleomagnetic pattern shows 7 m of chalk of reversed polarity containing in its upper part the marine Cretaceous-Tertiary biostratigraphic boundary. A greensand deposit contains numerous re-deposited Maastrichtian fossils. The fossils show no signs of wear and are of very different sizes including 1 mm thick juvenile belemnites. The deposit was described as a lag-sediment. Among the various fossils are teeth of mosasaurs. Thus there is coincidence in time between the extinction of mosasaurs and other Cretaceous organisms. This leads to the conclusion, that extinction of terrestrial dinosaurs took place earlier than extinction of marine dinosaurs at the Cretaceous-Tertiary boundary.

  3. The first Late Cretaceous (Maastrichtian dinosaur footprints from Transylvania (Romania

    Directory of Open Access Journals (Sweden)

    Matei Vremir

    2002-09-01

    Full Text Available An Uppermost Cretaceous (Maastrichtian site exposing dinosaur footprints is reported from the Sebes̡ area (Transylvanian Depression. This is the first dinoturbated layer discovered in our country, containing also numerous bones belonging to various dinosaurs. The track-site is located near Lancrăm village and provides only two quite well preserved footprints (one track. The medium sized (FL = 23,3 cm; FW = 17,8 cm; pace = 103 cm; ST = 200 cm plantigrad-tridactyle footprints belong to Ornithopedoidei, according to their morphology. An assignment to the Iguanodontichnus CASAMIQUELA & FASOLA, 1968 group seems to be appropriate (tentatively, associated to the “Rhabdodon” iguanodontian dinosaur. The importance of this discovery lies in the stratigraphical significance, confirming the Uppermost Cretaceous age of these dinosaur-bearing continental deposits exposed between Sebes̡ and Alba-Iulia (as well as the autochthon/ paraautochon status of some vertebrate assemblages identified there, which previously were considered Oligocene or even Miocene. Additional data regarding size, speed and locomotion of the Transylvanian Iguanodontian ”Rhabdodon” dinosaurs are added.

  4. Fossilized melanosomes and the colour of Cretaceous dinosaurs and birds.

    Science.gov (United States)

    Zhang, Fucheng; Kearns, Stuart L; Orr, Patrick J; Benton, Michael J; Zhou, Zhonghe; Johnson, Diane; Xu, Xing; Wang, Xiaolin

    2010-02-25

    Spectacular fossils from the Early Cretaceous Jehol Group of northeastern China have greatly expanded our knowledge of the diversity and palaeobiology of dinosaurs and early birds, and contributed to our understanding of the origin of birds, of flight, and of feathers. Pennaceous (vaned) feathers and integumentary filaments are preserved in birds and non-avian theropod dinosaurs, but little is known of their microstructure. Here we report that melanosomes (colour-bearing organelles) are not only preserved in the pennaceous feathers of early birds, but also in an identical manner in integumentary filaments of non-avian dinosaurs, thus refuting recent claims that the filaments are partially decayed dermal collagen fibres. Examples of both eumelanosomes and phaeomelanosomes have been identified, and they are often preserved in life position within the structure of partially degraded feathers and filaments. Furthermore, the data here provide empirical evidence for reconstructing the colours and colour patterning of these extinct birds and theropod dinosaurs: for example, the dark-coloured stripes on the tail of the theropod dinosaur Sinosauropteryx can reasonably be inferred to have exhibited chestnut to reddish-brown tones.

  5. An assessment of Hyalella azteca burrowing activity under laboratory sediment toxicity testing conditions.

    Science.gov (United States)

    Doig, Lorne E; Liber, Karsten

    2010-09-01

    Burrowing of the freshwater amphipod Hyalella azteca was evaluated under laboratory conditions similar to those recommended for standard sediment toxicity testing in Canada (EPS 1/RM/33; Environment Canada, 1997) and the United States (EPA/600/R-99/064; US EPA, 2000). Sediment type, time of day (light versus dark), size of animal, and the presence or absence of food were varied to assess their effects on burrowing activity. Hyalella azteca were found to burrow rapidly in fine, organic-rich sediments, but were slower to burrow in a sandy sediment. There was no increase in the number of animals occupying the sediment surface of a fine, organic-rich sediment after 4h of darkness compared to the previous 4h of light. Over a 9- to 10-d duration, a higher percentage of animals occupied the surface of the sandy sediment. The addition of food promoted burrowing in sandy sediment, as did using smaller animals. Overall, longer-duration tests involving older animals and coarse sediments may require formal observation to confirm burrowing and ensure adequate sediment exposure. The addition of food during a test may promote the burrowing of larger animals in coarse sediments, but may not be necessary in field-collected sediments that are not excessively sandy.

  6. Spatial and social organization in a burrow-dwelling lizard (Phrynocephalus vlangalii) from China.

    Science.gov (United States)

    Qi, Yin; Noble, Daniel W A; Fu, Jinzhong; Whiting, Martin J

    2012-01-01

    Shared ecological resources such as burrow complexes can set the stage for social groupings and the evolution of more complex social behavior such as parental care. Paternity testing is increasingly revealing cases of kin-based groupings, and lizards may be a good system to inform on the early evolution of sociality. We examined spatial and social organization in the lizard Phrynocephalus vlangalii from China and tested genetic relatedness (based on eight microsatellite DNA loci) between offspring and parents that shared burrow complexes. Adult males and females had similar spatial patterns: they overlapped most with members of the opposite sex and least with their own sex. Males in better body condition overlapped with more females, and both sexes showed high site fidelity. Most lizards used a single burrow, but some individuals used two or three burrows. While high site fidelity is consistent with sociality in lizards, juveniles did not preferentially share burrows with parents, and we documented only a few cases of parent-offspring associations through burrow sharing. We suggest that P. vlangalii conforms to a classical polygynous mating system in which the burrow forms the core of the male's territory and may be offered as an important resource for females, but this remains to be determined.

  7. Large-diameter burrows of the Triassic Ischigualasto Basin, NW Argentina: paleoecological and paleoenvironmental implications.

    Directory of Open Access Journals (Sweden)

    Carina E Colombi

    Full Text Available Large-diameter ichnofossils comprising three morphotypes have been identified in the Upper Triassic Ischigualasto and Los Colorados formations of northwestern Argentina. These burrows add to the global record of the early appearance of fossorial behavior during early Mesozoic time. Morphotypes 1 and 2 are characterized by a network of tunnels and shafts that can be assigned to tetrapod burrows given similarities with previously described forms. However, differences in diameter, overall morphology, and stratigraphic occurrence allow their independent classification. Morphotype 3 forms a complex network of straight branches that intersect at oblique angles. Their calcareous composition and surface morphology indicate these structures have a composite biogenic origin likely developed due to combined plant/animal interactions. The association of Morphotypes 1 and 2 with fluvial overbank lithologies deposited under an extremely seasonal arid climate confirms interpretations that the early appearance of burrowing behavior was employed by vertebrates in response to both temperature and moisture-stress associated with seasonally or perpetually dry Pangean paleoclimates. Comparisons of burrow morphology and biomechanical attributes of the abundant paleovertebrate fauna preserved in both formations permit interpretations regarding the possible burrow architects for Morphotypes 1 and 2. In the case of the Morphotype 1, the burrow constructor could be one of the small carnivorous cynodonts, Ecteninion or Probelesodon. Assigning an architect for Morphotype 2 is more problematic due to mismatches between the observed burrow morphology and the size of the known Los Colorados vertebrates.

  8. Spatial and social organization in a burrow-dwelling lizard (Phrynocephalus vlangalii from China.

    Directory of Open Access Journals (Sweden)

    Yin Qi

    Full Text Available Shared ecological resources such as burrow complexes can set the stage for social groupings and the evolution of more complex social behavior such as parental care. Paternity testing is increasingly revealing cases of kin-based groupings, and lizards may be a good system to inform on the early evolution of sociality. We examined spatial and social organization in the lizard Phrynocephalus vlangalii from China and tested genetic relatedness (based on eight microsatellite DNA loci between offspring and parents that shared burrow complexes. Adult males and females had similar spatial patterns: they overlapped most with members of the opposite sex and least with their own sex. Males in better body condition overlapped with more females, and both sexes showed high site fidelity. Most lizards used a single burrow, but some individuals used two or three burrows. While high site fidelity is consistent with sociality in lizards, juveniles did not preferentially share burrows with parents, and we documented only a few cases of parent-offspring associations through burrow sharing. We suggest that P. vlangalii conforms to a classical polygynous mating system in which the burrow forms the core of the male's territory and may be offered as an important resource for females, but this remains to be determined.

  9. Synchrotron Reveals Early Triassic Odd Couple: Injured Amphibian and Aestivating Therapsid Share Burrow.

    Directory of Open Access Journals (Sweden)

    Vincent Fernandez

    Full Text Available Fossorialism is a beneficial adaptation for brooding, predator avoidance and protection from extreme climate. The abundance of fossilised burrow casts from the Early Triassic of southern Africa is viewed as a behavioural response by many tetrapods to the harsh conditions following the Permo-Triassic mass-extinction event. However, scarcity of vertebrate remains associated with these burrows leaves many ecological questions unanswered. Synchrotron scanning of a lithified burrow cast from the Early Triassic of the Karoo unveiled a unique mixed-species association: an injured temnospondyl amphibian (Broomistega that sheltered in a burrow occupied by an aestivating therapsid (Thrinaxodon. The discovery of this rare rhinesuchid represents the first occurrence in the fossil record of a temnospondyl in a burrow. The amphibian skeleton shows signs of a crushing trauma with partially healed fractures on several consecutive ribs. The presence of a relatively large intruder in what is interpreted to be a Thrinaxodon burrow implies that the therapsid tolerated the amphibian's presence. Among possible explanations for such unlikely cohabitation, Thrinaxodon aestivation is most plausible, an interpretation supported by the numerous Thrinaxodon specimens fossilised in curled-up postures. Recent advances in synchrotron imaging have enabled visualization of the contents of burrow casts, thus providing a novel tool to elucidate not only anatomy but also ecology and biology of ancient tetrapods.

  10. Chemically mediated burrow recognition in the Mexican tarantula Brachypelma vagans female

    Science.gov (United States)

    Dor, Ariane; Machkour-M'rabet, Salima; Legal, Luc; Williams, Trevor; Hénaut, Yann

    2008-12-01

    Chemically mediated communication is common in spiders but has been poorly studied in burrowing tarantulas. This study aimed to determine whether chemical cues influence the behaviour of females of Brachypelma vagans, a Mexican species of tarantula, during encounters with previously inhabited burrows or with extracts from the silk of conspecific females. In laboratory choice tests, female tarantulas entered a burrow that had previously been inhabited by a conspecific female significantly more frequently than a burrow that had never been inhabited. The identity of the previous inhabitant also affected the number of spiders that chose to enter a burrow. Spiders were quicker to choose and enter a burrow previously inhabited by themselves than a burrow previously inhabited by a conspecific or a burrow that had not been previously inhabited. Hexane, methanol and dichloromethane extracts of conspecific silk elicited different responses from female tarantulas when extracts were placed on filter paper disks at one end of an experimental arena with a control filter paper disk, on to which the corresponding solvent alone had been pipetted, placed on the other end of the arena. Spiders showed the strongest responses to hexane extracts of silk, with a significant preference to move towards the hexane extract and a significantly greater period of time spent in proximity to the hexane extract compared to the control disk. Overall and in contrast to expectations, tarantulas were most strongly attracted to the cues left by other conspecific females. As encounters between B. vagans females usually lead to aggression and mortality of one of the participants, we conclude that chemical cues are not signals that are deliberately released by burrow-inhabiting females but may inadvertently escape and cannot be easily suppressed.

  11. Similar burrow architecture of three arid-zone scorpion species implies similar ecological function

    Science.gov (United States)

    Adams, Amanda M.; Marais, Eugene; Turner, J. Scott; Prendini, Lorenzo; Pinshow, Berry

    2016-08-01

    Many animals reside in burrows that may serve as refuges from predators and adverse environmental conditions. Burrow design varies widely among and within taxa, and these structures are adaptive, fulfilling physiological (and other) functions. We examined the burrow architecture of three scorpion species of the family Scorpionidae: Scorpio palmatus from the Negev desert, Israel; Opistophthalmus setifrons, from the Central Highlands, Namibia; and Opistophthalmus wahlbergii from the Kalahari desert, Namibia. We hypothesized that burrow structure maintains temperature and soil moisture conditions optimal for the behavior and physiology of the scorpion. Casts of burrows, poured in situ with molten aluminum, were scanned in 3D to quantify burrow structure. Three architectural features were common to the burrows of all species: (1) a horizontal platform near the ground surface, long enough to accommodate the scorpion, located just below the entrance, 2-5 cm under the surface, which may provide a safe place where the scorpion can monitor the presence of potential prey, predators, and mates and where the scorpion warms up before foraging; (2) at least two bends that might deter incursion by predators and may reduce convective ventilation, thereby maintaining relatively high humidity and low temperature; and (3) an enlarged terminal chamber to a depth at which temperatures are almost constant (±2-4 °C). These common features among the burrows of three different species suggest that they are important for regulating the physical environment of their inhabitants and that burrows are part of scorpions' "extended physiology" ( sensu Turner, Physiol Biochem Zool 74:798-822, 2000).

  12. Offene Lizenzen in den Digitalen Geisteswissenschaften

    Directory of Open Access Journals (Sweden)

    Kirsten Süselbeck

    2015-07-01

    Full Text Available Bericht über die vom Münchner Zentrum für digitale Geisteswissenschaften organisierten Tagung „Offene Lizenzen in den Digitalen Geisteswissenschaften“ am 27. und 28. April 2015

  13. Reform af reformen - den nye ellov

    DEFF Research Database (Denmark)

    Olsen, Ole Jess

    2005-01-01

    Konkurrence i dansk elforsyning blev i første omgang i 1999 kun gennemført halvhjertet. Den miljøvenlige energi blev holdt uden for og selskabsstrukturen låst fast. Det skabte problemer, som den nye lov fra 2004 har søgt at råde bod på.......Konkurrence i dansk elforsyning blev i første omgang i 1999 kun gennemført halvhjertet. Den miljøvenlige energi blev holdt uden for og selskabsstrukturen låst fast. Det skabte problemer, som den nye lov fra 2004 har søgt at råde bod på....

  14. Motivation af den Kreative Sælger

    OpenAIRE

    Sørensen, Mikkel Vallentin; Floor, Jeppe Hjelmsted

    2012-01-01

    Projektet tager udgangspunkt i motivationen af danske sælgere. Med inspiration fra den positive psykologiske videnskab, udfordres eksisterende motivationsredskaber, med henblik på at motivere den enkelte medarbejder til at yde et bedre stykke arbejde for virksomheden. Daniel Pink, Bruno Frey og Frederick Herzberg danner det teoretiske grundlag for opgaven, og problemstillingen undersøges gennem en sammenholdelse af deres teorier med empirisk materiale i en fænomenologisk tilgang. Rapporten af...

  15. Hvorfor al den snak om etik?

    DEFF Research Database (Denmark)

    Hjort, Katrin

    2010-01-01

    Denne artikel handler om pædagogers professionsetik, og om hvordan pædagoger – som andre velfærdsprofessionelle inden for uddannelse, sundhed og socialt arbejde – i dag er spændt ud mellem på den ene side den klassiske velfærdsstats pligtetik, kravet om at give ”alt det bedste til alle”, og på de...

  16. Biomechanics (Communication arising): prey attack by a large theropod dinosaur.

    Science.gov (United States)

    Frazzetta, T H; Kardong, Kenneth V

    2002-03-28

    Prey-capture strategies in carnivorous dinosaurs have been inferred from the biomechanical features of their tooth structure, the estimated bite force produced, and their diet. Rayfield et al. have used finite-element analysis (FEA) to investigate such structure-function relationships in Allosaurus fragilis, and have found that the skull was designed to bear more stress than could be generated by simple biting. They conclude that this large theropod dinosaur delivered a chop-and-slash 'hatchet' blow to its prey, which it approached with its mouth wide open before driving its upper tooth row downwards. We argue that this mode of predation is unlikely, and that the FEA results, which relate to an 'overengineered' skull, are better explained by the biomechanical demands of prey capture. Understanding the mechanics of predation is important to our knowledge of the feeding habits of carnivorous dinosaurs and for accurate reconstruction their lifestyles.

  17. Epidermal and dermal integumentary structures of ankylosaurian dinosaurs.

    Science.gov (United States)

    Arbour, Victoria M; Burns, Michael E; Bell, Phil R; Currie, Philip J

    2014-01-01

    Ankylosaurian dinosaurs are most notable for their abundant and morphologically diverse osteoderms, which would have given them a spiky appearance in life. Isolated osteoderms are relatively common and provide important information about the structure of the ankylosaur dermis, but fossilized impressions of the soft-tissue epidermis of ankylosaurs are rare. Nevertheless, well-preserved integument exists on several ankylosaur fossils that shows osteoderms were covered by a single epidermal scale, but one or many millimeter-sized ossicles may be present under polygonal, basement epidermal scales. Evidence for the taxonomic utility of ankylosaurid epidermal scale architecture is presented for the first time. This study builds on previous osteological work that argues for a greater diversity of ankylosaurids in the Dinosaur Park Formation of Alberta than has been traditionally recognized and adds to the hypothesis that epidermal skin impressions are taxonomically relevant across diverse dinosaur clades.

  18. Bird embryos uncover homology and evolution of the dinosaur ankle.

    Science.gov (United States)

    Ossa-Fuentes, Luis; Mpodozis, Jorge; Vargas, Alexander O

    2015-11-13

    The anklebone (astragalus) of dinosaurs presents a characteristic upward projection, the 'ascending process' (ASC). The ASC is present in modern birds, but develops a separate ossification centre, and projects from the calcaneum in most species. These differences have been argued to make it non-comparable to dinosaurs. We studied ASC development in six different orders of birds using traditional techniques and spin-disc microscopy for whole-mount immunofluorescence. Unexpectedly, we found the ASC derives from the embryonic intermedium, an ancient element of the tetrapod ankle. In some birds it comes in contact with the astragalus, and, in others, with the calcaneum. The fact that the intermedium fails to fuse early with the tibiale and develops an ossification centre is unlike any other amniotes, yet resembles basal, amphibian-grade tetrapods. The ASC originated in early dinosaurs along changes to upright posture and locomotion, revealing an intriguing combination of functional innovation and reversion in its evolution.

  19. Bird embryos uncover homology and evolution of the dinosaur ankle

    Science.gov (United States)

    Ossa-Fuentes, Luis; Mpodozis, Jorge; Vargas, Alexander O

    2015-01-01

    The anklebone (astragalus) of dinosaurs presents a characteristic upward projection, the ‘ascending process' (ASC). The ASC is present in modern birds, but develops a separate ossification centre, and projects from the calcaneum in most species. These differences have been argued to make it non-comparable to dinosaurs. We studied ASC development in six different orders of birds using traditional techniques and spin–disc microscopy for whole-mount immunofluorescence. Unexpectedly, we found the ASC derives from the embryonic intermedium, an ancient element of the tetrapod ankle. In some birds it comes in contact with the astragalus, and, in others, with the calcaneum. The fact that the intermedium fails to fuse early with the tibiale and develops an ossification centre is unlike any other amniotes, yet resembles basal, amphibian-grade tetrapods. The ASC originated in early dinosaurs along changes to upright posture and locomotion, revealing an intriguing combination of functional innovation and reversion in its evolution. PMID:26563435

  20. The first dinosaur from Washington State and a review of Pacific coast dinosaurs from North America.

    Science.gov (United States)

    Peecook, Brandon R; Sidor, Christian A

    2015-01-01

    We describe the first diagnostic dinosaur fossil from Washington State. The specimen, which consists of a proximal left femur, was recovered from the shallow marine rocks of the Upper Cretaceous (Campanian) Cedar District Formation (Nanaimo Group) and is interpreted as pertaining to a large theropod on the basis of its hollow medullary cavity and proximally placed fourth trochanter. The Washington theropod represents one of the northernmost occurrences of a Mesozoic dinosaur on the west coast of the United States and one of only a handful from the Pacific coast of Laramidia during the Cretaceous. Its isolated nature and preservation in marine rocks suggest that the element was washed in from a nearby fluvial system. If the femur pertains to a tyrannosauroid, which seems likely given its size and the widespread occurrence of the group across Laramidia during Late Cretaceous times, then it would represent an earlier occurrence of large body size than previously recognized (complete femur length estimated at 1.2 meters). Uncertainty surrounding the latitude of deposition of the Nanaimo Group (i.e., the Baja-British Columbia hypothesis) precludes assigning the Washington theropod to either of the putative northern or southern biogeographic provinces of Laramidia.

  1. At traversere den Andens fantasi eller at traversere fantasien om den Anden

    DEFF Research Database (Denmark)

    Hansen, Brian Benjamin

    2016-01-01

    Fantasier lærer os at begære, hedder det hos Lacan. De sætter os i kontakt med den Andens begær. Men kan man egentlig komme for tæt på den Anden? Hvad sker der, når man kommer for tæt på den Andens fantasier? Og hvad sker der, når man kommer for tæt på fantasien om den Anden? Disse og lignende...

  2. Biomechanics of running indicates endothermy in bipedal dinosaurs.

    Directory of Open Access Journals (Sweden)

    Herman Pontzer

    Full Text Available BACKGROUND: One of the great unresolved controversies in paleobiology is whether extinct dinosaurs were endothermic, ectothermic, or some combination thereof, and when endothermy first evolved in the lineage leading to birds. Although it is well established that high, sustained growth rates and, presumably, high activity levels are ancestral for dinosaurs and pterosaurs (clade Ornithodira, other independent lines of evidence for high metabolic rates, locomotor costs, or endothermy are needed. For example, some studies have suggested that, because large dinosaurs may have been homeothermic due to their size alone and could have had heat loss problems, ectothermy would be a more plausible metabolic strategy for such animals. METHODOLOGY/PRINCIPAL FINDINGS: Here we describe two new biomechanical approaches for reconstructing the metabolic rate of 14 extinct bipedal dinosauriforms during walking and running. These methods, well validated for extant animals, indicate that during walking and slow running the metabolic rate of at least the larger extinct dinosaurs exceeded the maximum aerobic capabilities of modern ectotherms, falling instead within the range of modern birds and mammals. Estimated metabolic rates for smaller dinosaurs are more ambiguous, but generally approach or exceed the ectotherm boundary. CONCLUSIONS/SIGNIFICANCE: Our results support the hypothesis that endothermy was widespread in at least larger non-avian dinosaurs. It was plausibly ancestral for all dinosauriforms (perhaps Ornithodira, but this is perhaps more strongly indicated by high growth rates than by locomotor costs. The polarity of the evolution of endothermy indicates that rapid growth, insulation, erect postures, and perhaps aerobic power predated advanced "avian" lung structure and high locomotor costs.

  3. Sauropod dinosaurs evolved moderately sized genomes unrelated to body size.

    Science.gov (United States)

    Organ, Chris L; Brusatte, Stephen L; Stein, Koen

    2009-12-22

    Sauropodomorph dinosaurs include the largest land animals to have ever lived, some reaching up to 10 times the mass of an African elephant. Despite their status defining the upper range for body size in land animals, it remains unknown whether sauropodomorphs evolved larger-sized genomes than non-avian theropods, their sister taxon, or whether a relationship exists between genome size and body size in dinosaurs, two questions critical for understanding broad patterns of genome evolution in dinosaurs. Here we report inferences of genome size for 10 sauropodomorph taxa. The estimates are derived from a Bayesian phylogenetic generalized least squares approach that generates posterior distributions of regression models relating genome size to osteocyte lacunae volume in extant tetrapods. We estimate that the average genome size of sauropodomorphs was 2.02 pg (range of species means: 1.77-2.21 pg), a value in the upper range of extant birds (mean = 1.42 pg, range: 0.97-2.16 pg) and near the average for extant non-avian reptiles (mean = 2.24 pg, range: 1.05-5.44 pg). The results suggest that the variation in size and architecture of genomes in extinct dinosaurs was lower than the variation found in mammals. A substantial difference in genome size separates the two major clades within dinosaurs, Ornithischia (large genomes) and Saurischia (moderate to small genomes). We find no relationship between body size and estimated genome size in extinct dinosaurs, which suggests that neutral forces did not dominate the evolution of genome size in this group.

  4. Dynamics of dental evolution in ornithopod dinosaurs

    Science.gov (United States)

    Strickson, Edward; Prieto-Márquez, Albert; Benton, Michael J.; Stubbs, Thomas L.

    2016-07-01

    Ornithopods were key herbivorous dinosaurs in Mesozoic terrestrial ecosystems, with a variety of tooth morphologies. Several clades, especially the ‘duck-billed’ hadrosaurids, became hugely diverse and abundant almost worldwide. Yet their evolutionary dynamics have been disputed, particularly whether they diversified in response to events in plant evolution. Here we focus on their remarkable dietary adaptations, using tooth and jaw characters to examine changes in dental disparity and evolutionary rate. Ornithopods explored different areas of dental morphospace throughout their evolution, showing a long-term expansion. There were four major evolutionary rate increases, the first among basal iguanodontians in the Middle-Late Jurassic, and the three others among the Hadrosauridae, above and below the split of their two major clades, in the middle of the Late Cretaceous. These evolutionary bursts do not correspond to times of plant diversification, including the radiation of the flowering plants, and suggest that dental innovation rather than coevolution with major plant clades was a major driver in ornithopod evolution.

  5. Dynamics of dental evolution in ornithopod dinosaurs

    Science.gov (United States)

    Strickson, Edward; Prieto-Márquez, Albert; Benton, Michael J.; Stubbs, Thomas L.

    2016-01-01

    Ornithopods were key herbivorous dinosaurs in Mesozoic terrestrial ecosystems, with a variety of tooth morphologies. Several clades, especially the ‘duck-billed’ hadrosaurids, became hugely diverse and abundant almost worldwide. Yet their evolutionary dynamics have been disputed, particularly whether they diversified in response to events in plant evolution. Here we focus on their remarkable dietary adaptations, using tooth and jaw characters to examine changes in dental disparity and evolutionary rate. Ornithopods explored different areas of dental morphospace throughout their evolution, showing a long-term expansion. There were four major evolutionary rate increases, the first among basal iguanodontians in the Middle-Late Jurassic, and the three others among the Hadrosauridae, above and below the split of their two major clades, in the middle of the Late Cretaceous. These evolutionary bursts do not correspond to times of plant diversification, including the radiation of the flowering plants, and suggest that dental innovation rather than coevolution with major plant clades was a major driver in ornithopod evolution. PMID:27412496

  6. Global aspects of dinosaur distribution and evolution

    Energy Technology Data Exchange (ETDEWEB)

    Sues, H.

    1988-02-01

    Late Jurassic dinosaurian assemblages show close taxonomic correspondence over wide geographical ranges. Presently available if meager evidence suggests that this is also the case for Early Cretaceous communities. Cretaceous dinosaurian assemblages of Campanian and Maastrichtian age show considerable geographical differentiation but also some wide-ranging genera. Northern Hemisphere terrestrial ecosystems were dominated by hadrosaurs and ceratopsians, both herbivores with advanced capabilities for oral food-processing, whereas Southern Hemisphere biota were characterized by the abundance of titanosaurid sauropods, which relied on gut processing. Very close taxonomic similarities exist between the Campanian and early Maastrichtian dinosaurian assemblages of Mongolia and western North America, which, in part, is matched by similarities among other tetrapods such as mammals. Endemic dinosaurs in the Southern Hemisphere appear to reflect major changes in continental configuration. Some evidence exists for interchange of fuanal elements between North and South America. In absence of late Maastrichtian dinosaurian assemblages from most regions, scenarios concerning the terminal Cretaceous extinction of the Dinosauria should be regarded with caution because they are exclusively based on the conditions in western North America.

  7. Broad-scale patterns of late jurassic dinosaur paleoecology.

    Directory of Open Access Journals (Sweden)

    Christopher R Noto

    Full Text Available BACKGROUND: There have been numerous studies on dinosaur biogeographic distribution patterns. However, these distribution data have not yet been applied to ecological questions. Ecological studies of dinosaurs have tended to focus on reconstructing individual taxa, usually through comparisons to modern analogs. Fewer studies have sought to determine if the ecological structure of fossil assemblages is preserved and, if so, how dinosaur communities varied. Climate is a major component driving differences between communities. If the ecological structure of a fossil locality is preserved, we expect that dinosaur assemblages from similar environments will share a similar ecological structure. METHODOLOGY/PRINCIPAL FINDINGS: This study applies Ecological Structure Analysis (ESA to a dataset of 100+ dinosaur taxa arranged into twelve composite fossil assemblages from around the world. Each assemblage was assigned a climate zone (biome based on its location. Dinosaur taxa were placed into ecomorphological categories. The proportion of each category creates an ecological profile for the assemblage, which were compared using cluster and principal components analyses. Assemblages grouped according to biome, with most coming from arid or semi-arid/seasonal climates. Differences between assemblages are tied to the proportion of large high-browsing vs. small ground-foraging herbivores, which separates arid from semi-arid and moister environments, respectively. However, the effects of historical, taphonomic, and other environmental factors are still evident. CONCLUSIONS/SIGNIFICANCE: This study is the first to show that the general ecological structure of Late Jurassic dinosaur assemblages is preserved at large scales and can be assessed quantitatively. Despite a broad similarity of climatic conditions, a degree of ecological variation is observed between assemblages, from arid to moist. Taxonomic differences between Asia and the other regions demonstrate at

  8. Amerikaniseringen af den danske fagbevægelse

    DEFF Research Database (Denmark)

    Knudsen, Dino

    den amerikanske fagbevægelse der - bistået af CIA - førte an i den internationale kampagne mod kommunismen. Hermed blev danskerne involveret i hemmelige efterretningsoperationer, lyssky pengeoverførsler og var med til at splitte den internationale fagbevægelse. Den danske arbejderbevægelse spillede en...

  9. Behavioural adaptations to moisture as an environmental constraint in a nocturnal burrow-inhabiting Kalahari detritivore Parastizopus armaticeps Peringuey (Coleoptera: Tenebrionidae

    Directory of Open Access Journals (Sweden)

    O.A.E. Rasa

    1994-09-01

    Full Text Available The nocturnal desert detritivore Parastiz.opus armaticeps shows differences in surface activity patterns and burrow fidelity depending on surface humidity. After rain approximately half of the beetle population, independent of sex, is highly vagile and disperses over long distances. During drought, beetles are more sedentary and show higher burrow fidelity. They also inhabit burrows that are longer and deeper than non-inhabited ones, such burrows being relatively scarce. Burrow fidelity and the adoption of a more sedentary habit during drought are considered strategies to avoid the risks of not locating a suitable burrow before sunrise and subsequent desiccation in shallow burrows.

  10. Status assessment and conservation plan for the western burrowing owl in the United States

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Western Burrowing Owl (Athene cunicularia hypugaea) is a grassland specialist distributed throughout w. North America, primarily in open areas with short...

  11. Rodents new to the diet of the western burrowing owl(athene CUNICULARIA HYPUGAEA )

    Science.gov (United States)

    Wiluford, D.L.; Woodin, M.C.; Skoruppa, M.K.; Hickman, G.C.

    2009-01-01

    The northern pygmy mouse (Baiomys taylori), fulvous harvest mouse (Reithrodontomys fulvescens), and Merriam's pocket mouse (Pemgnathus merriami) are new to the diet of the western burrowing owl (Athene cuniculana hypugaed). All three species were identified from remains in regurgitated pellets collected from roost sites of burrowing owls in southern Texas over a period of 4 winters. Together, northern pygmy mice and fulvous harvest mice represented 58% of mammals identified in 182 pellets regurgitated by western burrowing owls. Merriam's pocket mouse accounted for only 4% of identified mammalian prey. Frequency of occurrence in pellets was 16% for northern pygmv mice, 11% for fulvous harvest mice, and 3% for Merriam's pocket mice. The primary reason for absence of these species in previous studies of foods of western burrowing owls is that most were conducted in latitudes north of these southern-distributed species of mammals.

  12. Colorado Plateau Rapid Ecoregion Assessment Conservation Elements - Terrestrial Species: Burrowing Owl

    Data.gov (United States)

    Bureau of Land Management, Department of the Interior — This map shows the potential current distribution of burrowing owl, in the context of current and near-term terrestrial intactness and long-term potential for...

  13. Crab burrows as conduits for groundwater-surface water exchange in Bangladesh

    Science.gov (United States)

    Stahl, Mason O.; Tarek, M. H.; Yeo, Darren C. J.; Badruzzaman, A. B. M.; Harvey, Charles F.

    2014-12-01

    Groundwater recharge affects water budgets and groundwater quality on the deltas and floodplains of South and Southeast Asia. Rain and flooding rivers recharge groundwater during the monsoon; irrigated rice fields and surface water bodies recharge aquifers during the dry season. Groundwater throughout the region is severely contaminated by arsenic, and recent research suggests that quantifying and characterizing recharge is important to understand whether recharge flushes or mobilizes arsenic from aquifers. At a field site in Bangladesh, we found that burrows of terrestrial crabs short-circuit low-permeability surface sediments, providing the primary conduit for recharge. We combine field observations along with a model that couples isotope and water balances to quantify the effect of crab burrows on aquifer recharge. Given the wide distribution of burrowing crabs and the surficial geology, we suggest that crab burrows provide widespread conduits for groundwater recharge.

  14. EPA Removes Burrows Sanitation Site in Michigan from National List of Most Contaminated Sites

    Science.gov (United States)

    For Immediate Release No. 15-OPA142 CHICAGO - The U.S. Environmental Protection Agency today announced that the Burrows Sanitation Superfund site in Hartford Township, Van Buren County, Michigan, has been officially removed from the Agency's l

  15. The first 50Myr of dinosaur evolution: macroevolutionary pattern and morphological disparity.

    Science.gov (United States)

    Brusatte, Stephen L; Benton, Michael J; Ruta, Marcello; Lloyd, Graeme T

    2008-12-23

    The evolutionary radiation of dinosaurs in the Late Triassic and Early Jurassic was a pivotal event in the Earth's history but is poorly understood, as previous studies have focused on vague driving mechanisms and have not untangled different macroevolutionary components (origination, diversity, abundance and disparity). We calculate the morphological disparity (morphospace occupation) of dinosaurs throughout the Late Triassic and Early Jurassic and present new measures of taxonomic diversity. Crurotarsan archosaurs, the primary dinosaur 'competitors', were significantly more disparate than dinosaurs throughout the Triassic, but underwent a devastating extinction at the Triassic-Jurassic boundary. However, dinosaur disparity showed only a slight non-significant increase after this event, arguing against the hypothesis of ecological release-driven morphospace expansion in the Early Jurassic. Instead, the main jump in dinosaur disparity occurred between the Carnian and Norian stages of the Triassic. Conversely, dinosaur diversity shows a steady increase over this time, and measures of diversification and faunal abundance indicate that the Early Jurassic was a key episode in dinosaur evolution. Thus, different aspects of the dinosaur radiation (diversity, disparity and abundance) were decoupled, and the overall macroevolutionary pattern of the first 50Myr of dinosaur evolution is more complex than often considered.

  16. Structural extremes in a cretaceous dinosaur.

    Science.gov (United States)

    Sereno, Paul C; Wilson, Jeffrey A; Witmer, Lawrence M; Whitlock, John A; Maga, Abdoulaye; Ide, Oumarou; Rowe, Timothy A

    2007-11-21

    Fossils of the Early Cretaceous dinosaur, Nigersaurus taqueti, document for the first time the cranial anatomy of a rebbachisaurid sauropod. Its extreme adaptations for herbivory at ground-level challenge current hypotheses regarding feeding function and feeding strategy among diplodocoids, the larger clade of sauropods that includes Nigersaurus. We used high resolution computed tomography, stereolithography, and standard molding and casting techniques to reassemble the extremely fragile skull. Computed tomography also allowed us to render the first endocast for a sauropod preserving portions of the olfactory bulbs, cerebrum and inner ear, the latter permitting us to establish habitual head posture. To elucidate evidence of tooth wear and tooth replacement rate, we used photographic-casting techniques and crown thin sections, respectively. To reconstruct its 9-meter postcranial skeleton, we combined and size-adjusted multiple partial skeletons. Finally, we used maximum parsimony algorithms on character data to obtain the best estimate of phylogenetic relationships among diplodocoid sauropods. Nigersaurus taqueti shows extreme adaptations for a dinosaurian herbivore including a skull of extremely light construction, tooth batteries located at the distal end of the jaws, tooth replacement as fast as one per month, an expanded muzzle that faces directly toward the ground, and hollow presacral vertebral centra with more air sac space than bone by volume. A cranial endocast provides the first reasonably complete view of a sauropod brain including its small olfactory bulbs and cerebrum. Skeletal and dental evidence suggests that Nigersaurus was a ground-level herbivore that gathered and sliced relatively soft vegetation, the culmination of a low-browsing feeding strategy first established among diplodocoids during the Jurassic.

  17. Structural extremes in a cretaceous dinosaur.

    Directory of Open Access Journals (Sweden)

    Paul C Sereno

    Full Text Available Fossils of the Early Cretaceous dinosaur, Nigersaurus taqueti, document for the first time the cranial anatomy of a rebbachisaurid sauropod. Its extreme adaptations for herbivory at ground-level challenge current hypotheses regarding feeding function and feeding strategy among diplodocoids, the larger clade of sauropods that includes Nigersaurus. We used high resolution computed tomography, stereolithography, and standard molding and casting techniques to reassemble the extremely fragile skull. Computed tomography also allowed us to render the first endocast for a sauropod preserving portions of the olfactory bulbs, cerebrum and inner ear, the latter permitting us to establish habitual head posture. To elucidate evidence of tooth wear and tooth replacement rate, we used photographic-casting techniques and crown thin sections, respectively. To reconstruct its 9-meter postcranial skeleton, we combined and size-adjusted multiple partial skeletons. Finally, we used maximum parsimony algorithms on character data to obtain the best estimate of phylogenetic relationships among diplodocoid sauropods. Nigersaurus taqueti shows extreme adaptations for a dinosaurian herbivore including a skull of extremely light construction, tooth batteries located at the distal end of the jaws, tooth replacement as fast as one per month, an expanded muzzle that faces directly toward the ground, and hollow presacral vertebral centra with more air sac space than bone by volume. A cranial endocast provides the first reasonably complete view of a sauropod brain including its small olfactory bulbs and cerebrum. Skeletal and dental evidence suggests that Nigersaurus was a ground-level herbivore that gathered and sliced relatively soft vegetation, the culmination of a low-browsing feeding strategy first established among diplodocoids during the Jurassic.

  18. Fossils and Dinosaurs--A Fully Integrated Instructional Unit.

    Science.gov (United States)

    Kuehl, Matt; And Others

    This lesson plan for the second and third grades uses information on dinosaurs, their adaptations and survival, to provide science education for limited-English-proficient (LEP) students in San Diego, California. The primary text is "Los Dinosaurios Gigantes," a core literature book used in the school district. Lessons are based on the whole…

  19. Metric-Asaurus: Conceptualizing Scale Using Dinosaur Models

    Science.gov (United States)

    Gloyna, Lisa; West, Sandra; Martin, Patti; Browning, Sandra

    2010-01-01

    For middle school students who have seen only pictures of dinosaurs in books, in the movies, or on the internet, trying to comprehend the size of these gargantuan animals can be difficult. This lesson provides a way for students to visualize changing scale through studying extinct organisms and to gain a deeper understanding of the history of the…

  20. TeV scale gravity, mirror universe, and ... dinosaurs

    CERN Document Server

    Silagadze, Z K

    2001-01-01

    This is somewhat extended version of the talk given at the Gran Sasso SummerInstitute: Massive Neutrinos in Physics and Astrophysics. It describes generalideas about mirror world, extra spatial dimensions and dinosaur extinction.Some suggestions are made how these seemingly different things can be relatedto each other.

  1. Dinosaur demise in light of their alleged perennial polar residency

    Science.gov (United States)

    Lewy, Zeev

    2016-12-01

    The end-Cretaceous biological crisis is represented by the demise of the non-avian dinosaurs. However, most crucial biologically was the elimination of the photosynthesizing marine phyto- and zooplankton forming the base of the marine food chain. Their abrupt demise attests to sunlight screening darkening the atmosphere for a few years. Alvarez et al. (Science 208:1095-1108, 1980. doi: 10.1126/science.208.44) noticed in deep marine end-Cretaceous sediments an anomalous rise in the chemical element iridium (Ir), which is rare on planet Earth and thus suggests an extraterrestrial origin through an impact of a large asteroid. This impact would have ejected enormous quantities of particles and aerosols, shading the solar illumination as attested to by the elimination of the marine photosynthesizing plankton. Such a dark period must have affected life on land. The apparent cold-blooded non-avian dinosaurs, which were used to living in open terrains to absorb the solar illumination, became inactive during the dark period and were incapable of withstanding predators. This was in contrast to cold-blooded crocodilians, turtles and lizards that could hide in refuge sites on land and in the water. Dinosaur relics discovered in Cretaceous Polar Regions were attributed to perennial residents, surviving the nearly half-year-long dark winter despite their ability to leave. The polar concentrations of disarticulated dinosaur bones were suggested as having resulted from a catastrophic burial of a population by floods. However, this should have fossilized complete skeletons. Alternatively, herds of dinosaurs living in high latitudes might have been sexually driven to spend the half year of continuously illuminated polar summer for mating rather than for nourishment, in which the lower latitudes provided as well. The aggressive mating competitions would have left victims among the rivals and of young ones incidentally trampled over, all being consumed and their skeletons

  2. Leadership pipeline i den offentlige sektor

    DEFF Research Database (Denmark)

    Dahl, Kristian Aagaard; Molly-Søholm, Thorkil

    en rejse ind i hjertet af offentlig ledelse med fokus på lederniveauerne: topchef, funktionel chef, leder af ledere og leder af medarbejdere. Med afsæt i righoldige eksempler og fortællinger fra virkeligheden introduceres læseren for ledelsesteorien den Offentlige Leadership Pipeline, som giver...... enkelte lederniveauer og udvikle ledertalenter. Teorien byder på et detaljeret ledelsesgrundlag, hvorudfra den offentlige organisation kan bygge en professionel værdikæde for ledelse ved at forme lederprofiler, -rekruttering, -uddannelse, -evaluering m.m. Leadership Pipeline i den offentlige sektor er...... baseret på et treårigt dansk praksisorienteret forskningsprojekt med deltagelse af 15 offentlige organisationer, som repræsenterer kommunerne, regionerne og staten. Projektet har videreudviklet en af de sidste 10 års mest indflydelsesrige ledelseteorier i de største private organisationer, Leadership...

  3. De frygtsomme og den smalle palet

    DEFF Research Database (Denmark)

    Skude, Flemming

    2003-01-01

    Om den konventionelle modernismes bandlysning af alle farver på nær hvid - og om bl.a. Luis Barragan som et vellykket eksempel på at farver kan bringe arkitektur op i et højere perceptionsniveau.......Om den konventionelle modernismes bandlysning af alle farver på nær hvid - og om bl.a. Luis Barragan som et vellykket eksempel på at farver kan bringe arkitektur op i et højere perceptionsniveau....

  4. Farvel til globaliseringen som vi kendte den

    DEFF Research Database (Denmark)

    Böss, Michael

    2009-01-01

    Vi er endt med en krise, som rækker langt ud over det globale monetære system, fordi den ideologiske ortodoksi, der skabte den, har ført til udflytning af millioner af arbejdspladser, tæring af nationalstaternes sammenhængskraft og overgreb på naturen. Kronikken refererer bl.a. til John Maynard K...... Keynes og en artikel af økonomen Robert Skidelsky i The American Prospect. Udgivelsesdato: 12. januar 2009...

  5. Der westliche Blick auf den Orient

    Directory of Open Access Journals (Sweden)

    Antje Schrupp

    2007-11-01

    Full Text Available Angesichts der aktuellen Debatten über den Islam zeigen Christina von Braun und Bettina Mathes die viele Jahrhunderte alte Interpretationsgeschichte des Orients aus westlicher Perspektive auf. In ihrem materialreichen Band schildern sie die historische und geografische Vielfalt des Phänomens „Islam“ und zeigen, wie westliches Selbstverständnis und Projektionen das Bild des Okzidents vom Orient seit langem und bis heute prägen – auch da, wo man es auf den ersten Blick nicht vermuten würde.

  6. Construindo um Densímetro

    OpenAIRE

    Ricetti Rodrigo

    2002-01-01

    Para fins didáticos, é apresentada uma maneira de construir um densímetro, aparelho utilizadopara medir a densidade de fluidos. um aparato fácil de ser construído e muito simples de serutilizado. Sua principal vantagem sobre os densímetros que comercialmente encontramos, é a suacapacidade de medir a densidade de quaisquer líquidos, operando em qualquer faixa de densidade. Outra vantagem que apresenta, é a possibilidade de fazer uma medição relativa entre quaisquerlíquidos, não fazendo apenas ...

  7. Pathologic bone tissues in a Turkey vulture and a nonavian dinosaur: implications for interpreting endosteal bone and radial fibrolamellar bone in fossil dinosaurs.

    Science.gov (United States)

    Chinsamy, Anusuya; Tumarkin-Deratzian, Allison

    2009-09-01

    We report on similar pathological bone microstructure in an extant turkey vulture (Cathartes aura) and a nonavian dinosaur from Transylvania. Both these individuals exhibit distinctive periosteal reactive bone deposition accompanied by endosteal bone deposits in the medullary cavity. Our findings have direct implications on the two novel bone tissues recently described among nonavian dinosaurs, radial fibrolamellar bone tissue and medullary bone tissue. On the basis of the observed morphology of the periosteal reactive bone in the turkey vulture and the Transylvanian dinosaur, we propose that the radial fibrolamellar bone tissues observed in mature dinosaurs may have had a pathological origin. Our analysis also shows that on the basis of origin, location, and morphology, pathologically derived endosteal bone tissue can be similar to medullary bone tissues described in nonavian dinosaurs. As such, we caution the interpretation of all endosteally derived bone tissue as homologous to avian medullary bone.

  8. Growth patterns in brooding dinosaurs reveals the timing of sexual maturity in non-avian dinosaurs and genesis of the avian condition.

    Science.gov (United States)

    Erickson, Gregory M; Curry Rogers, Kristina; Varricchio, David J; Norell, Mark A; Xu, Xing

    2007-10-22

    The timing of sexual maturation in non-avian dinosaurs is not known. In extant squamates and crocodilians it occurs in conjunction with the initial slowing of growth rates as adult size is approached. In birds (living dinosaurs) on the other hand, reproductive activity begins well after somatic maturity. Here we used growth line counts and spacing in all of the known brooding non-avian dinosaurs to determine the stages of development when they perished. It was revealed that sexual maturation occurred well before full adult size was reached-the primitive reptilian condition. In this sense, the life history and physiology of non-avian dinosaurs was not like that of modern birds. Palaeobiological ramifications of these findings include the potential to deduce reproductive lifespan, fecundity and reproductive population sizes in non-avian dinosaurs, as well as aid in the identification of secondary sexual characteristics.

  9. Map-Based Repowering and Reorganization of a Wind Resource Area to Minimize Burrowing Owl and Other Bird Fatalities

    Directory of Open Access Journals (Sweden)

    Lee Neher

    2009-10-01

    Full Text Available Wind turbines in the Altamont Pass Wind Resource Area (Alameda/Contra Costa Counties, California, USA generate about 730 GWh of electricity annually, but have been killing thousands of birds each year, including >2,000 raptors and hundreds of burrowing owls. We have developed collision hazard maps and hazard ratings of wind turbines to guide relocation of existing wind turbines and careful repowering to modern turbines to reduce burrowing owl fatalities principally, and other birds secondarily. Burrowing owls selected burrow sites lower on slopes and on smaller, shallower slopes than represented by the average 10 × 10 m2 grid cell among 187,908 grid cells sampled from 2,281,169 grid cells comprising a digital elevation model (DEM of the study area. Fuzzy logic and discriminant function analysis produced likelihood surfaces encompassing most burrowing owl burrows within a fraction of the study area, and the former corresponded with burrowing owl fatalities and the latter with other raptor fatalities. Our ratings of wind turbine hazard were more predictive of burrowing owl fatalities, but would be more difficult to implement. Careful repowering to modern wind turbines would most reduce fatalities of burrowing owls and other birds while adding about 1,000 GWh annually toward California’s 33% Renewable Portfolio Standard.

  10. Effect of particle size frequency distribution of the substratum on the burrowing ability of Chiridota rigida (semper) (Echinodermata: holothuroidea)

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, J.M.; Murdoch, J.

    1977-01-01

    Chiridota rigida (Semper) burrows easily into well-sorted substrata, moving between particles in coarse substrata and pushing aside particles in fine substrata. Chiridota rigida does not burrow easily into poorly sorted substrata because spaces which can be penetrated are not available and because the particles cannot be moved as a result of increased stability of the substratum. In poorly sorted substrata, burrowing ability increases with increases in the proportion of fine particles. It would appear that the distribution and abundance of chiridota rigida and other chiridotids would be affected by the effect of the substratum on their ability to burrow.

  11. Den fragmentariske by og det 'gode byliv'

    DEFF Research Database (Denmark)

    Pløger, J.

    Gennem en række betragtninger på bylivets værdier og normer, de bymæssige livsformer og livsstile udleder forfatteren, at den danske by- og boligplanlægning ikke i tilstrækkelig grad afspejler 'de ægte byborgeres' identifikation med bylivet og deres krav til bomiljøet. Mange singler, studerende, ...

  12. The Oscars og den klassiske Hollywoodfilm

    DEFF Research Database (Denmark)

    Nielsen, Jakob Isak

    2013-01-01

    Artiklen diskuterer, hvorvidt Oscaruddelingen har været med til at konsolidere de normer og traditioner, der kendetegner den klassiske Hollywoodfilm som et (fortællemæssigt) paradigme. Der tages afsæt i Oscarvindere fra Wings (1927) og frem til It Happened One Night (1934). Artiklen konkluderer...

  13. Portræt: Den koreanske dansker

    DEFF Research Database (Denmark)

    Henriksen, Carsten

    2009-01-01

    Lene Myong Petersen har som den første i Danmark skrevet ph.d.-afhandling om adoption. Og ifølge Lene Myong Petersen er det belastede begreb om race ikke til at slippe uden om, hvis man vil forstå vilkårene for adopterede i Danmark....

  14. - den bedste, troeste og smukkeste Lighed

    DEFF Research Database (Denmark)

    Vejlby, Anna Schram

    Afhandlingen fortolker C.W. Eckersbergs portrætter ud fra formelle, filosofiske og sociale synsvinkler. Afhandlingen bevæger sig fra samfund til subjekt, fra ydre omstændigheder til indre rørelser, fra overordnede europæiske strømninger inden for kunst og filosofi til den subjektive oplevelse af...

  15. Den professionelle kommunikations renæssance

    Directory of Open Access Journals (Sweden)

    Niels Chr. Nielsen

    1993-09-01

    Full Text Available Mens hovedparten af den nyere PR-litteratur bevæger sig "på kommu- nikations niveau", og blot beskriver fremtidens virksomhedskommuni- kation i forhold til fortidens og nutidens kommunikationsformer, så gra- ver Niels Chr. Nielsen i denne artikel et par spadestik dybere. Han beskriver kort den igangværende erhvervsstrukturelle og teknologiske udvikling og trækker dernæst paralleller til kravene til virksomhedernes professionelle kommunikationsarbejde. Det er hans tese, at den tekno- logiske og erhvervsstukturelle udvikling ikke, som ofte påstået, fører til mere og mere sofistikeret manipulation med modtagerne; tværtimod vil det der ske en forskydning i argumentets og den ægte dialogs retning. Niels Chr. Nielsen, der er cand.mag i filosofi og idehistorie, skriver fra en position som udviklingsdirektør ved Dansk Teknologisk Institut. Artiklen er et bearbejdet oplæg fra konferencen "Excellent Public Relations", 18. marts 1993.

  16. De Pretertiaire Historie van den Indischen Archipel

    NARCIS (Netherlands)

    Umbgrove, J.H.F.

    1935-01-01

    Aan de hand van een serie kaartjes wordt in deze studie gepoogd de ontwikkeling van den Indischen Archipel — verspreiding van land en zee, faciesgebieden, tijden van transgressies, plooiingsperiodes etc. — in pretertiairen tijd voor zoover mogelijk na te gaan. Bij het vermelden van feiten en van lit

  17. Evidensbaseret viden i den klinske sygepleje

    DEFF Research Database (Denmark)

    Andres, Emilie Marie; Larsen, Bente Malig

    2008-01-01

    University College Lillebælt, Sygeplejerskeuddannelsen i Svendborg og Odense har i efteråret 2007 og foråret 2008 arbejdet med projekt ’Uddannelse af kliniske vejledere i anvendelse af evidensbaseret viden i den kliniske sygepleje’. Projektet slutter efter planen i efteråret 2008. Projektet går ud...

  18. Tre teorier om den moralske udvikling

    DEFF Research Database (Denmark)

    Bo, Inger Glavind; Andreasen, Brian Kjær

    I artiklen gennemgås tre forskellige men teorihistorisk relaterede perspektiver på forståelsen af moralsk udvikling: Piaget, Kohlberg og Gilligan. I den efterfølgende diskussion af disse teoretikeres respektive positioner påpeges såvel forskelle som ligheder i deres betoning af moralens karakter...

  19. Læring og den kulturhistoriske skole

    DEFF Research Database (Denmark)

    Broström, Stig

    2007-01-01

    Vygotskys forståelse og kredsen omkring ham, bl.a. Leontjev, Luria, Levinia, Slavinia, Zaporozhets, Elkonin m.fl., samt en række nyere overvejende amerikanske Vygotskys-forskeres arbejder, medlemmer af den såkaldte CHAT-gruppen (Cultural Historical Activity Theory), bl.a. Michael Cole, Yrjö Engeström, Loiz...

  20. Demokratiseringen af den politiske diskurs i Polen

    DEFF Research Database (Denmark)

    Arnfast, Juni Søderberg

    1999-01-01

    Gennem en analyse af brugen af personlige pronominer i politiske tekster fra udvalgte, polske medier diskuteres forandringerne i den polske, politiske diskurs gennem 1980'erne. Det påvises at det kommunistiske styres anvendelse af pronominet 'vi' skifter konnotationer i retning af en mindre ideol...

  1. Den skrøbelige sandhed

    DEFF Research Database (Denmark)

    Pedersen, Peter Ole

    2010-01-01

    Artiklen retter fokus mod de seneste års udvikling af den aktivistiske dokumentarfilm. Med analytiske punktnedslag hos instruktørerne Michael Moore, Morgan Spurlock, Dylan Avery, Robert Greenwald og Mauro Andrizzi undersøges de forbindelser der eksisterer mellem udtrykket i de populære spillefilm...

  2. Den udødelige gangster

    DEFF Research Database (Denmark)

    Bjerre, Thomas Ærvold

    2009-01-01

    Hollywood har igennem et århundrede hyldet de voldspsykopater, som de fleste gangstere nu engang er. Michael Manns Public Enemies er seneste skud på stammen i den lange række af amerikanske gangsterfilm, der tog sin begyndelse i starten af 1930'erne, og som meget hurtig blev til en mytisk...

  3. Flaskevand - den rene vare i brandingens tidsalder

    DEFF Research Database (Denmark)

    Hermansen, Judy

    2008-01-01

    At tappe vand på flasker er blevet den mest udbredte globale virksomhed overhovedet, og forbruget af flaskevand stiger fortsat hurtigt - især i lande hvor man kan få rent drikkevand direkte fra hanen gratis eller til en meget billig penge. Hvorfor er vi havnet i sådan et tilsyneladende paradoksal...

  4. Den drikfældige engel?

    DEFF Research Database (Denmark)

    Eriksen, Sidsel

    1991-01-01

    Artiklen opfatter kvinders særlige drikkemønstre som et udslag af kultur og ikke (blot) som en konsekvens af kvindens særlige biologi. Udgangspunktet er, at drikkeri ikke passer sammen med den traditionelle kvinderolle. Endnu værre er det dog, hvis kvinder drak i offentligheden. Det er formentlig...

  5. Robotter – den asymmetriske krigs soldater?

    DEFF Research Database (Denmark)

    Helms, Niels Henrik

    2010-01-01

    Teknologien remedierer krigen. Robotterne er indrulleret i det militære arsenal, som vigtige aktører, men især den asymmetriske krig er en krig om folks hjerter, hvor beslutningstagerne må afveje prisen for indsatsen med nødvendigheden af at være tilstede. Og alle er til stede: robotterne, soldat...

  6. Dr. Bakhuizen van den Brink retires

    NARCIS (Netherlands)

    Kalkman, C.

    1976-01-01

    On 11 September 1976 dr. Reinier Cornelis Bakhuizen van den Brink will reach the age of 65 and so he must retire from his position as a senior botanist at the Rijksherbarium. He has worked in our institute since December 1943, after having obtained his doctor’s degree in Utrecht. At the Rijksherbari

  7. A phylogenetic study of the section moduli of the humerus in bipedal theropod dinosaurs

    Science.gov (United States)

    Lee, Scott; Richards, Zachary

    The section modulus of a bone is a measure of its ability to resist bending torques. Carnivorous dinosaurs including Tyrannosauroidea and Allosauroidea had strong humeri, presumably to hold struggling prey during hunting. The herbivorous dinosaurs of Ornithomimosauria had weak arm bones. This is believed to reflect the fact that their arms were never subjected to large bending torques. The unusual dinosaurs of Therizinosauria had arms as strong as found in the carnivorous dinosaurs. This is consistent with the hypothesis that their manus suggests a digging lifestyle. Other groups including Oviraptorosauria, Troodontidae, Dromaeosauridae and Compsognathidae are also examined.

  8. Paleobiological implications of dinosaur egg-bearing deposits in the Cretaceous Gyeongsang Supergroup of Korea

    Science.gov (United States)

    Paik, In Sung; Kim, Hyun Joo; Huh, Min

    2010-05-01

    Dinosaur egg-bearing deposits in the Cretaceous Gyeongsang Basin in Korea is described in taphonomic aspect, their paleoenvironments are interpreted, and geobiological implications of dinosaur egg-bearing deposits in the world and Korea are analyzed in geographic occurrences, geological ages, paleoenvironments, and lithology. Dinosaur eggs with spheroolithids, faveoloolithid, and elongatoolithid structural types occur in several stratigraphic formations of the Cretaceous Gyeongsang Basin in South Korea, and most of the egg-bearing formations are the Late Cretaceous. The dinosaur eggs usually occur as clutches in purple sandy mudstone of floodplain deposits preserved as calcic paleosol with association of vertic paleosol features in places. Most of the eggs are top-broken and filled with surrounding sediments. The general depositional environment of dinosaur egg deposits in the Gyeongsang Supergroup are interpreted as a dried floodplain where volcanic activity occurred intermittently in the vicinity of the nesting sites. Their depositional settings on which floodplains developed are diverse from fluvial plain with meandering rivers to alluvial plain with episodic sheet flooding. The nesting areas in the Gyeongsang Basin are deemed to have been under semi-arid climate, which resulted in formation of calcic soils facilitating preservation of the dinosaur eggs. The geochronologic occurrences of dinosaur egg-bearing deposits are mostly restricted to the Late Cretaceous in the world as well as in Korea. If it has not been resulted from biased discoveries and reports of dinosaur eggs, biological rather than physical and chemical conditions for preservation of dinosaur eggs might be related with the restricted occurrences in the Late Cretaceous. Two hypotheses are suggested for probable biological causes to the geochronologically restricted occurrences of dinosaur egg-bearing deposits. One is related with the appearance of angiosperms in the Late Jurassic and the spreading

  9. Hepatische Effekte von Wachstumshormon auf den Glukosestoffwechsel

    Directory of Open Access Journals (Sweden)

    Rufinatscha K

    2015-01-01

    Full Text Available Untherapierter Wachstumshormonmangel im Erwachsenenalter (AGHD ist mit viszeraler Adipositas, Dyslipidämie, Insulinresistenz und Fettleber verbunden. Interessanterweise finden sich viele der AGHD-Merkmale auch bei Patienten mit metabolischem Syndrom. Die nichtalkoholische Fettlebererkrankung (NAFLD gilt als hepatische Manifestation des metabolischen Syndroms. In einigen Studien wurden bei Patienten mit NAFLD verminderte Konzentrationen von zirkulierendem IGF-1, dessen Synthese zu einem großen Teil durch Wachstumshormon (GH reguliert wird, beschrieben. Mäuse, welche eine hepatische Wachstumshormondefizienz aufweisen, zeigen zahlreiche phänotypische Charakteristika des metabolischen Syndroms, unter anderen auch eine Fettlebererkrankung. Dies legt einen Zusammenhang zwischen dem Wachstumshormon und der Entstehung einer NAFLD nahe. Ziel unserer Studie ist es, in einem Zellkulturmodell die Effekte des Wachstumshormons auf den intrazellulären Glukosestoffwechsel näher zu untersuchen. Im Detail sollen Auswirkungen einer verminderten Wachstumshormonrezeptorexpression auf den Insulinsignaltransduktionsweg, den Glykogengehalt und auf Schlüsselenzyme der Glukoneogenese untersucht werden. Präliminäre Daten zeigen, dass eine verminderte Wachstumshormonrezeptorexpression mit intrazellulären Veränderungen des hepatischen Glukosestoffwechsels verbunden ist. Die verminderte Insulinsensitivität könnte auf Alterationen im Insulinsignaltransduktionsweg und Änderungen der Glukoneogenese zurückzuführen sein. Diese präliminären Daten weisen darauf hin, dass Wachstumshormon einen direkten Einfluss auf den Glukosestoffwechsel in der Leber hat. Zudem legen sie nahe, dass Veränderungen im Wachstumshormonstoffwechsel einen wichtigen pathophysiologischen Mechanismus in der Entstehung der Fettlebererkrankung bei Patienten mit metabolischem Syndrom darstellen könnten. Der folgende Artikel soll einen kurzen Überblick über die Effekte von Wachstumshormon

  10. An Integrated Experimental and Modeling Approach to Predict Sediment Mixing from Benthic Burrowing Behavior.

    Science.gov (United States)

    Roche, Kevin R; Aubeneau, Antoine F; Xie, Minwei; Aquino, Tomás; Bolster, Diogo; Packman, Aaron I

    2016-09-20

    Bioturbation is the dominant mode of sediment transport in many aquatic environments and strongly influences both sediment biogeochemistry and contaminant fate. Available bioturbation models rely on highly simplified biodiffusion formulations that inadequately capture the behavior of many benthic organisms. We present a novel experimental and modeling approach that uses time-lapse imagery to directly relate burrow formation to resulting sediment mixing. We paired white-light imaging of burrow formation with fluorescence imaging of tracer particle redistribution by the oligochaete Lumbriculus variegatus. We used the observed burrow formation statistics and organism density to parametrize a parsimonious model for sediment mixing based on fundamental random walk theory. Worms burrowed over a range of times and depths, resulting in homogenization of sediments near the sediment-water interface, rapid nonlocal transport of tracer particles to deep sediments, and large areas of unperturbed sediments. Our fundamental, parsimonious random walk model captures the central features of this highly heterogeneous sediment bioturbation, including evolution of the sediment-water interface coupled with rapid near-surface mixing and anomalous late-time mixing resulting from infrequent, deep burrowing events. This approach provides a general, transferable framework for explicitly linking sediment transport to governing biophysical processes.

  11. Den første kunsthistorie var romersk

    DEFF Research Database (Denmark)

    Isager, Jacob Erik

    2013-01-01

    Plinius den Ældres afsnit om skulptur og maleri som inspiration for senere kunsthistorier og kunstnere......Plinius den Ældres afsnit om skulptur og maleri som inspiration for senere kunsthistorier og kunstnere...

  12. Opera til folket? - Den Jyske Opera 70 år

    DEFF Research Database (Denmark)

    Bonde, Lars Ole

    2017-01-01

    Introduktion til Den Jyske Operas 70 års jubilæumsforestilling og programnoter til samtlige numre.......Introduktion til Den Jyske Operas 70 års jubilæumsforestilling og programnoter til samtlige numre....

  13. Den Europæiske Union som liberalistisk medborgerprojekt

    DEFF Research Database (Denmark)

    Agustin, Lise Rolandsen

    2005-01-01

    Den Europæiske Union (EU) befinder sig i en ufrivillig tænkepause efter den franske afvisning af Traktaten om en forfatning for Europa ved folkeafstemningen den 20. maj 2005. Det er således tid til at reflektere over, hvori det europæiske samarbejde består i dag, og over, hvorledes det kan eller ...

  14. Premolarized double dens in dente in albinism - A case report

    Directory of Open Access Journals (Sweden)

    Suprabha B

    2005-09-01

    Full Text Available Dens in dente are known to be associated with many dental abnormalities such as taurodontism microdontia, gemination, and dens evaginatus. This paper describes a rare case of double dens in dente in a lateral incisor with crown morphology similar to a premolar present in a patient with features of albinism. Problems associated with this condition and their management is discussed.

  15. Det lille land før den store krig

    DEFF Research Database (Denmark)

    Clemmesen, Michael Hesselholt

    Krige i Nordafrika og på Balkan. Den Store Krig truede. Den tyske marine brugte danske farvande som sine egne, men den unge, aggressive britiske marineminister Churchill ville nu presse sin flåde ind i Kattegat, uden hensyn til dansk og svensk neutralitet, i risikable operationer, der kunne udløse...

  16. Bibemærkninger til den kognitive kapitalisme

    DEFF Research Database (Denmark)

    Petersen, Lars Axel

    2009-01-01

    Med den franske økonom Yann Moulier-Boutangs vision om pollensamfundet sættes viden - og ikke mindst vores forståelse af vidensarbejderen - i et nyt lys. Lars Axel Pedersen analyserer, med Marx under den ene arm og Lyotard under den anden, forestillingen om de fritsvævende og altbestøvende...

  17. An abelisauroid theropod dinosaur from the Turonian of Madagascar.

    Directory of Open Access Journals (Sweden)

    Andrew A Farke

    Full Text Available Geophysical evidence strongly supports the complete isolation of India and Madagascar (Indo-Madagascar by ∼100 million years ago, though sparse terrestrial fossil records from these regions prior to ∼70 million years ago have limited insights into their biogeographic history during the Cretaceous. A new theropod dinosaur, Dahalokely tokana, from Turonian-aged (∼90 million years old strata of northernmost Madagascar is represented by a partial axial column. Autapomorphies include a prominently convex prezygoepipophyseal lamina on cervical vertebrae and a divided infraprezygapophyseal fossa through the mid-dorsal region, among others. Phylogenetic analysis definitively recovers the species as an abelisauroid theropod and weakly as a noasaurid. Dahalokely is the only known dinosaur from the interval during which Indo-Madagascar likely existed as a distinct landmass, but more complete material is needed to evaluate whether or not it is more closely related to later abelisauroids of Indo-Madagascar or those known elsewhere in Gondwana.

  18. A gigantic feathered dinosaur from the lower cretaceous of China.

    Science.gov (United States)

    Xu, Xing; Wang, Kebai; Zhang, Ke; Ma, Qingyu; Xing, Lida; Sullivan, Corwin; Hu, Dongyu; Cheng, Shuqing; Wang, Shuo

    2012-04-04

    Numerous feathered dinosaur specimens have recently been recovered from the Middle-Upper Jurassic and Lower Cretaceous deposits of northeastern China, but most of them represent small animals. Here we report the discovery of a gigantic new basal tyrannosauroid, Yutyrannus huali gen. et sp. nov., based on three nearly complete skeletons representing two distinct ontogenetic stages from the Lower Cretaceous Yixian Formation of Liaoning Province, China. Y. huali shares some features, particularly of the cranium, with derived tyrannosauroids, but is similar to other basal tyrannosauroids in possessing a three-fingered manus and a typical theropod pes. Morphometric analysis suggests that Y. huali differed from tyrannosaurids in its growth strategy. Most significantly, Y. huali bears long filamentous feathers, thus providing direct evidence for the presence of extensively feathered gigantic dinosaurs and offering new insights into early feather evolution.

  19. An Early Cretaceous heterodontosaurid dinosaur with filamentous integumentary structures.

    Science.gov (United States)

    Zheng, Xiao-Ting; You, Hai-Lu; Xu, Xing; Dong, Zhi-Ming

    2009-03-19

    Ornithischia is one of the two major groups of dinosaurs, with heterodontosauridae as one of its major clades. Heterodontosauridae is characterized by small, gracile bodies and a problematic phylogenetic position. Recent phylogenetic work indicates that it represents the most basal group of all well-known ornithischians. Previous heterodontosaurid records are mainly from the Early Jurassic period (205-190 million years ago) of Africa. Here we report a new heterodontosaurid, Tianyulong confuciusi gen. et sp. nov., from the Early Cretaceous period (144-99 million years ago) of western Liaoning Province, China. Tianyulong extends the geographical distribution of heterodontosaurids to Asia and confirms the clade's previously questionable temporal range extension into the Early Cretaceous period. More surprisingly, Tianyulong bears long, singular and unbranched filamentous integumentary (outer skin) structures. This represents the first confirmed report, to our knowledge, of filamentous integumentary structures in an ornithischian dinosaur.

  20. [Von den Restgütern zu den Sowchosen in Estland 1939-1953. Dokumentensammlung] / Olev Liivik

    Index Scriptorium Estoniae

    Liivik, Olev, 1975-

    2011-01-01

    Arvustus: Von den Restgütern zu den Sowchosen in Estland 1939-1953 : Dokumentensammlung / Hrsg. von David Feest, Karsten Brüggemann. Berlin : Lit Verlag, 2010. (Schriften der Baltischen historischen Kommission ; Bd. 15)

  1. Influence of vegetation on the nocturnal foraging behaviors and vertebrate prey capture by endangered Burrowing Owls

    Directory of Open Access Journals (Sweden)

    Alan Marsh

    2014-06-01

    Full Text Available Restrictions in technology have limited past habitat selection studies for many species to the home-range level, as a finer-scale understanding was often not possible. Consequently, these studies may not identify the true mechanism driving habitat selection patterns, which may influence how such results are applied in conservation. We used GPS dataloggers with digital video recorders to identify foraging modes and locations in which endangered Burrowing Owls (Athene cunicularia captured prey. We measured the coarse and fine-scale characteristics of vegetation at locations in which owls searched for, versus where they caught, vertebrate prey. Most prey items were caught using hover-hunting. Burrowing Owls searched for, and caught, vertebrate prey in all cover types, but were more likely to kill prey in areas with sparse and less dense vegetative cover. Management strategies designed to increase Burrowing Owl foraging success in the Canadian prairies should try to ensure a mosaic of vegetation heights across cover types.

  2. Habitat requirements and burrowing depths of rodents in relation to shallow waste burial sites

    Energy Technology Data Exchange (ETDEWEB)

    Gano, K.A.; States, J.B.

    1982-05-01

    The purpose of this paper is to provide a review of the literature and summarize information on factors affecting habitat selection and maximum recorded burrowing depths for representative small mammals that we consider most likely to inhibit waste burial sites in arid and semi-arid regions of the West. The information is intended for waste management designers who need to know what to expect from small mammals that may be present at a particular site. Waste repositories oculd be designed to exclude the deep burrowing rodents of a region by creating an unattractive habitat over the waste. Summaries are given for habitat requirements of each group along with generalized modifications that could be employed to deter habitation. Representatives from the major groups considered to be deep burrowers are discussed. Further, detailed information about a particular species can be obtained from the references cited.

  3. Body temperatures in dinosaurs: what can growth curves tell us?

    Science.gov (United States)

    Griebeler, Eva Maria

    2013-01-01

    To estimate the body temperature (BT) of seven dinosaurs Gillooly, Alleen, and Charnov (2006) used an equation that predicts BT from the body mass and maximum growth rate (MGR) with the latter preserved in ontogenetic growth trajectories (BT-equation). The results of these authors evidence inertial homeothermy in Dinosauria and suggest that, due to overheating, the maximum body size in Dinosauria was ultimately limited by BT. In this paper, I revisit this hypothesis of Gillooly, Alleen, and Charnov (2006). I first studied whether BTs derived from the BT-equation of today's crocodiles, birds and mammals are consistent with core temperatures of animals. Second, I applied the BT-equation to a larger number of dinosaurs than Gillooly, Alleen, and Charnov (2006) did. In particular, I estimated BT of Archaeopteryx (from two MGRs), ornithischians (two), theropods (three), prosauropods (three), and sauropods (nine). For extant species, the BT value estimated from the BT-equation was a poor estimate of an animal's core temperature. For birds, BT was always strongly overestimated and for crocodiles underestimated; for mammals the accuracy of BT was moderate. I argue that taxon-specific differences in the scaling of MGR (intercept and exponent of the regression line, log-log-transformed) and in the parameterization of the Arrhenius model both used in the BT-equation as well as ecological and evolutionary adaptations of species cause these inaccuracies. Irrespective of the found inaccuracy of BTs estimated from the BT-equation and contrary to the results of Gillooly, Alleen, and Charnov (2006) I found no increase in BT with increasing body mass across all dinosaurs (Sauropodomorpha, Sauropoda) studied. This observation questions that, due to overheating, the maximum size in Dinosauria was ultimately limited by BT. However, the general high inaccuracy of dinosaurian BTs derived from the BT-equation makes a reliable test of whether body size in dinosaurs was ultimately limited

  4. Bone Cancer Rates in Dinosaurs Compared with Modern Vertebrates

    CERN Document Server

    Natarajan, L C; Rothschild, B M; Martin, L D

    2007-01-01

    Data on the prevalence of bone cancer in dinosaurs is available from past radiological examination of preserved bones. We statistically test this data for consistency with rates extrapolated from information on bone cancer in modern vertebrates, and find that there is no evidence of a different rate. Thus, this test provides no support for a possible role of ionizing radiation in the K-T extinction event.

  5. Body temperatures in dinosaurs: what can growth curves tell us?

    Directory of Open Access Journals (Sweden)

    Eva Maria Griebeler

    Full Text Available To estimate the body temperature (BT of seven dinosaurs Gillooly, Alleen, and Charnov (2006 used an equation that predicts BT from the body mass and maximum growth rate (MGR with the latter preserved in ontogenetic growth trajectories (BT-equation. The results of these authors evidence inertial homeothermy in Dinosauria and suggest that, due to overheating, the maximum body size in Dinosauria was ultimately limited by BT. In this paper, I revisit this hypothesis of Gillooly, Alleen, and Charnov (2006. I first studied whether BTs derived from the BT-equation of today's crocodiles, birds and mammals are consistent with core temperatures of animals. Second, I applied the BT-equation to a larger number of dinosaurs than Gillooly, Alleen, and Charnov (2006 did. In particular, I estimated BT of Archaeopteryx (from two MGRs, ornithischians (two, theropods (three, prosauropods (three, and sauropods (nine. For extant species, the BT value estimated from the BT-equation was a poor estimate of an animal's core temperature. For birds, BT was always strongly overestimated and for crocodiles underestimated; for mammals the accuracy of BT was moderate. I argue that taxon-specific differences in the scaling of MGR (intercept and exponent of the regression line, log-log-transformed and in the parameterization of the Arrhenius model both used in the BT-equation as well as ecological and evolutionary adaptations of species cause these inaccuracies. Irrespective of the found inaccuracy of BTs estimated from the BT-equation and contrary to the results of Gillooly, Alleen, and Charnov (2006 I found no increase in BT with increasing body mass across all dinosaurs (Sauropodomorpha, Sauropoda studied. This observation questions that, due to overheating, the maximum size in Dinosauria was ultimately limited by BT. However, the general high inaccuracy of dinosaurian BTs derived from the BT-equation makes a reliable test of whether body size in dinosaurs was ultimately

  6. Linking microbial enzymatic activities and functional diversity of soil around earthworm burrows and casts

    Directory of Open Access Journals (Sweden)

    Jerzy Lipiec

    2016-08-01

    Full Text Available The aim of this work was to evaluate the effect of earthworms (Lumbricidae on the enzymatic activity and microbial functional diversity in the burrow system (burrow wall 0–3 mm, transitional zone 3–7 mm, bulk soil >20 mm from the burrow wall and cast aggregates of a loess soil under a pear orchard. The dehydrogenase, β-glucosidase, protease, alkaline phosphomonoesterase, and acid phosphomonoesterase enzymes were assessed using standard methods. The functional diversity (catabolic potential was assessed using the Average Well Color Development and Richness Index following the community level physiological profiling from Biolog Eco Plates. All measurements were done using soil from each compartment immediately after in situ sampling in spring. The enzymatic activites including dehydrogenase, protease, β-glucosidase and alkaline phosphomonoesterase were appreciably greater in the burrow wall or casts than in bulk soil and transitional zone. Conversely, acid phosphomonoesterase had the largest value in the bulk soil. Average Well Color Development in both the transitional zone and the bulk soil (0.98-0.94 A590nm were more than eight times higher than in the burrow walls and casts. The lowest richness index in the bulk soil (15 utilized substrates increased by 86-113% in all the other compartments. The PC1 in principal component analysis (PCA mainly differentiated the burrow walls and the transitional zone. Utilization of all substrate categories was the lowest in the bulk soil. The PC2 differentiated the casts from the other compartments. The enhanced activity of a majority of the enzymes and increased microbial functional diversity in most earthworm-influenced compartments make the soils less vulnerable to degradation and thus increases the stability of ecologically relevant processes in the orchard ecosystem.

  7. Retrodeformation and muscular reconstruction of ornithomimosaurian dinosaur crania

    Directory of Open Access Journals (Sweden)

    Andrew R. Cuff

    2015-07-01

    Full Text Available Ornithomimosaur dinosaurs evolved lightweight, edentulous skulls that possessed keratinous rhamphothecae. Understanding the anatomy of these taxa allows for a greater understanding of “ostrich-mimic” dinosaurs and character change during theropod dinosaur evolution. However, taphonomic processes during fossilisation often distort fossil remains. Retrodeformation offers a means by which to recover a hypothesis of the original anatomy of the specimen, and 3D scanning technologies present a way to constrain and document the retrodeformation process. Using computed tomography (CT scan data, specimen specific retrodeformations were performed on three-dimensionally preserved but taphonomically distorted skulls of the deinocheirid Garudimimus brevipes Barsbold, 1981 and the ornithomimids Struthiomimus altus Lambe, 1902 and Ornithomimus edmontonicus Sternberg, 1933. This allowed for a reconstruction of the adductor musculature, which was then mapped onto the crania, from which muscle mechanical advantage and bite forces were calculated pre- and post-retrodeformation. The extent of the rhamphotheca was varied in each taxon to represent morphologies found within modern Aves. Well constrained retrodeformation allows for increased confidence in anatomical and functional analysis of fossil specimens and offers an opportunity to more fully understand the soft tissue anatomy of extinct taxa.

  8. A second look at the colors of the dinosaurs.

    Science.gov (United States)

    Turner, Derek D

    2016-02-01

    In earlier work, I predicted that we would probably not be able to determine the colors of the dinosaurs. I lost this epistemic bet against science in dramatic fashion when scientists discovered that it is possible to draw inferences about dinosaur coloration based on the microstructure of fossil feathers (Vinther et al., 2008). This paper is an exercise in philosophical error analysis. I examine this episode with two questions in mind. First, does this case lend any support to epistemic optimism about historical science? Second, under what conditions is it rational to make predictions about what questions scientists will or will not be able answer? In reply to the first question, I argue that the recent work on the colors of the dinosaurs matters less to the debate about the epistemology of historical science than it might seem. In reply to the second question, I argue that it is difficult to specify a policy that would rule out the failed bet without also being too conservative.

  9. An overview of the dinosaur fossil record from Chile

    Science.gov (United States)

    Rubilar-Rogers, David; Otero, Rodrigo A.; Yury-Yáñez, Roberto E.; Vargas, Alexander O.; Gutstein, Carolina S.

    2012-08-01

    In Chile, the record of dinosaurs in Jurassic and Cretaceous sediments is often restricted to footprints, with few skeletal remains. Tetanuran theropods are known in the Upper Jurassic, and bones of titanosaur sauropods in the Late Cretaceous, including partial skeletons (e.g. Atacamatitan chilensis Kellner et al.). Also from the late Cretaceous, an ornithopod vertebra, a pair of theropod teeth and one tarsometatarsus of a gaviiform bird (Neogaeornis wetzeli Lambrecht) have been reported. The Cenozoic fossil record comprises abundant and well-preserved marine birds from Eocene and Miocene units, with a specially abundant record of Sphenisciformes and less frequently, Procellariiformes. There is an excellent Miocene-Pliocene record of other birds such as Odontopterygiformes, including the most complete skeleton ever found of a pelagornithid, Pelagornis chilensis Mayr and Rubilar-Rogers. Fossil birds are also known from Pliocene and Pleistocene strata. A remarkable collection of birds was discovered in lacustrine sediments of late Pleistocene age associated to human activity. The perspectives in the study of dinosaurs in Chile are promising because plenty of material stored in institutional collections is not described yet. The record of Chilean dinosaurs is relevant for understanding the dynamics and evolution of this group of terrestrial animals in the western edge of Gondwana, while Cenozoic birds from the Region may contribute to the understanding of current biogeography for instance, the effect of the emergence and establishment of the Humboldt Current.

  10. Den Digital Kirkegårdskultur

    DEFF Research Database (Denmark)

    Sabra, Jakob Borrits

    2016-01-01

    , politiske og funktionelle dimensioner. Det for- udsætter et overblik over digitale fænomener og tendenser indenfor medieringer af døden i den danske kirkegårds- og mindekultur. Jeg vil således først give eksempler på, hvor- dan digitale teknologier og sociale medier kommer til udtryk i denne sammenhæng, og...... (primært vestlige) forskningslitteratur på området, vil jeg i denne artikel argumentere for, at kirkegården også har en voksende digital dimension, der kræver opmærk- somhed, holdningsudveksling og stillingtagen på samme vis som stedets religiøse, sekulære, æstetiske, sociale, kulturelle, historiske...

  11. Stephen Schwartz og den folkelige lyd

    DEFF Research Database (Denmark)

    Kreutzfeldt, Jacob

    2013-01-01

    Stephen Schwartz døde i foråret 2013. I denne artikel forsøger Jacob Kreutzfeldt, der gennemførte en række interviews med Schwartz gennem hans sidste år, at indkredse den æstetiske grundholdning, der prægede hans arbejde med radiomontagen i DR.......Stephen Schwartz døde i foråret 2013. I denne artikel forsøger Jacob Kreutzfeldt, der gennemførte en række interviews med Schwartz gennem hans sidste år, at indkredse den æstetiske grundholdning, der prægede hans arbejde med radiomontagen i DR....

  12. Studie af den amerikanske doktrin for Counterinsurgency

    DEFF Research Database (Denmark)

    Møller, Nicolai Stahlfest

    2006-01-01

    strategisk partner, og den mulige indsættelse i missioner, hvor kontakt med, og måske bekæmpelse af, fjendtlige oprørsbevægelser vil forekomme. Maos teori og den nyere radikale islams teori ses som værende repræsentative for oprørsbevægelser ift. både amerikanske erfaringer og det forventede danske...... synes også at være udtalt i imødegåelsen af radikal islam, hvilket er en stor udfordring for både militære og civile myndigheder og organisationer. For at fungere som COIN enhed kræver det veluddannede enheder, da de udover de basale soldateropgaver også skal kunne støtte ifm. CIMIC opgaver, løsning af...

  13. Behavioural and Physiological Implications of a Burrow-dwelling Lifestyle for Two Species of Upogebiid Mud-shrimp (Crustacea: Thalassinidea)

    Science.gov (United States)

    Astall, C. M.; Taylor, A. C.; Atkinson, R. J. A.

    1997-02-01

    Upogebia stellataand U. deltaura(Crustacea: Thalassinidea) construct burrows in nearshore sediments in U.K. waters. Burrow structure is similar in both species; the basic burrow consisting of a two-opening, U-shaped section with a vertical shaft descending from the mid-point of the U. This structure may be variously elaborated. Burrow cross-section is circular, dilations allow turning by somersaulting and surface openings are often constricted. Conditions within the burrows are usually hypoxic and hypercapnic. Burrow water PO 2in the parts normally occupied by the mud-shrimp was between 80-110 Torr, but was much lower (10-45 Torr) in the deepest, poorly-irrigated parts. Both species irrigate their burrows by episodes of pleopod beating of variable duration (mean=8·5±3·5 min and 2·8±0·5 min for U. deltauraand U. stellata, respectively), which draws oxygenated water into the burrow and also particulate food for suspension feeding. When exposed to hypoxia, U. deltauraand U. stellatawere able to maintain their rates of oxygen consumption approximately constant over a wide range of PO 2( Pc=30-50 Torr). Under these conditions, there was a pronounced increase in scaphognathite beat rate but heart rate remained relatively constant. Below the Pc, however, both rates declined.

  14. Variations in the Foraging Behaviour and Burrow Structures of the Damara Molerat Cryptomys damarensis in the Kalahari Gemsbok National Park

    Directory of Open Access Journals (Sweden)

    B.G. Lovegrove

    1987-10-01

    Full Text Available Aspects of two habitat-specific foraging behaviours of the social subterranean rodent Cryptomys damarensis, are discussed in terms of burrow structure, resource dispersion patterns, sand moisture content, burrow temperature regimes, and predatory pressures, in the Kalahari Gemsbok National Park, South Africa.

  15. Arzneimitteltherapie: Relevante Interaktionen und (negative Effekte auf den Knochen

    Directory of Open Access Journals (Sweden)

    Woschnagg H

    2003-01-01

    Full Text Available Dieses Review ist das Ergebnis einer Medline-Recherche. Demnach erscheinen die Auswirkungen der Genußgifte Alkohol, Nikotin und Kaffee auf den Knochen eher nachteilig zu sein. Nicht gering ist die Anzahl der Medikamente, die den Vitamin D-Stoffwechsel beeinflussen. Eine Androgenentzugstherapie beeinflußt den Knochenstoffwechsel negativ, Thyroxin hat diesen Effekt nur in einer deutlich suppressiv wirksamen Dosierung. Protonenpumpenhemmer verbessern die Resorption der Bisphosphonate sehr, Hydrochlorothiazide verhindern den renalen Kalziumverlust. Manche Statine und intermittierend verabreichte Nitrate scheinen ebenfalls günstige Auswirkungen auf den Knochen zu haben.

  16. Den gode præsentation

    DEFF Research Database (Denmark)

    Greve, Linda

    Den gode præsentation giver det teoretiske fundament og de praktiske værktøjer, der skal til for at skabe gode præsentationer, der virker efter hensigten. Læren er, at gode præsentationer kommer af grundig og metodisk velovervejet forberedelse – og af modet til at gå i relation med lytterne. Bogen...

  17. Optimisation of profits; Den Gewinn optimieren

    Energy Technology Data Exchange (ETDEWEB)

    Seltmann, T.

    1998-09-01

    In spite of the new taxation regulations for photovoltaic energy conversion systems, operators of PV systems can make profits. The contribution presents concrete examples. (orig.) [Deutsch] Durch den Verzicht auf die Kleinunternehmerregelung wird der Betreiber einer PV-Anlage zwar umsatzsteuerpflichtig. Wie dargestellt wird, kann er trotzdem auf Dauer einen Gewinn erwirtschaften. In diesem Beitrag wird anhand konkreter Beispiele erlaeutert, was der Betreiber tun muss, um seinen Anlagenertrag steuerlich korrekt und moeglichst gewinnbringend beim Fiskus anzugeben. (orig.)

  18. Den kontraktstyrede og kontraktstyrende offentlige sektor

    DEFF Research Database (Denmark)

    Schulze, Christiane; Greve, Carsten

    for levering af en service eller et produkt (Domberger 1998:12). Kontrakter er dog ikke bare en entydig formel aftale, der forstås på samme måde af enhver aktør. Tværtimod er kontrakter også afhængige af læsernes perspektiv såvel som omgivelsens normer, traditioner og legale rammer. Den er derved ikke...

  19. Open Access og Den Bibliometriske Forskningsindikator

    DEFF Research Database (Denmark)

    Dorch, Bertil

    2011-01-01

    I sine "Anbefalinger til implementering af Open Access i Danmark" foreslår det nationale Open Access Udvalget blandet andet, at Den Bibliometriske Forskningsindikator (BFI) bør koordineres med en national Open Access-politik. I dette paper, der er baseret på et blogindlæg, fremfører forfatteren...... fire grunde til, hvorfor han synes det er en dårlig idé at koble Open Access til BFI....

  20. Globale Entwikclung als Lernbereich in den Naturwissenschaften

    OpenAIRE

    Härtig, Hendrik; Bernholt, Sascha; Schroeter, Burkhard

    2014-01-01

    Mit dem Orientierungsrahmen für den Lernbereich Globale Entwicklung wurden Anregungen gegeben, die Themen nachhaltige Entwicklung und globale Entwicklung im Unterricht in allen Schulfächern aufzugreifen. Die drei naturwissenschaftlichen Schulfächer Biologie, Chemie und Physik haben sich bislang sehr unterschiedlich auf das Thema eingelassen. In der Biologiedidaktik finden sich sowohl Forschungsarbeiten als auch Unterrichtsvorschläge; für Chemie und insbesondere Physik existieren hingegen nur ...

  1. DENSITY-DEPENDENT IMPACTS OF BIOIRRIGATION BY THE BURROWING SHRIMP UPOGEBIA PUGETTENSIS ON BENTHIC FLUXES AND POREWATER SOLUTE DISTRIBUTIONS IN PACIFIC NORTHWEST ESTUARIES

    Science.gov (United States)

    Burrowing thalassinid shrimp are major ecosystem engineering species of Pacific estuaries and can structure the physical, chemical, and biotic properties of sediments. Feeding and burrow irrigation by benthic organisms can increase the remineralization rates of organic material (...

  2. Simultaneous Occurrence of Dens Invaginatus and Fusion

    Directory of Open Access Journals (Sweden)

    Amit Mhapuskar

    2013-01-01

    Full Text Available Although Dens invaginatus and fusion are well-known and well established dental anomalies, they are rarely seen in supernumerary teeth. In this article, simultaneous occurrence of Dens invaginatus and fusion between maxillary lateral incisor and a supernumerary tooth is described. Dens invaginatus is clinically significant due to the possibility of the pulpal involvement; pulpitis, necrotic pulps and chronic periapical lesions are often associated with this anomaly without clinical symptoms. Fusion has a negative impact on the aesthetics, especially when it occurs in maxillary anterior teeth. It is difficult to clinically make differential diagnosis between fused teeth and geminated teeth, especially when these anomalies take place together with hypodontia or supernumerary tooth. It has been found that sequel of such teeth may result in delayed eruption, ectopic eruption or even impaction of permanent teeth; hence proper diagnosis by clinical and radiographic methods and intervention at appropriate time is of paramount importance. The accurate knowledge of variations in morphology of tooth and pulp cavity greatly assists the dentist in planning successful treatment options.

  3. Construindo um Densímetro

    Directory of Open Access Journals (Sweden)

    Ricetti Rodrigo

    2002-01-01

    Full Text Available Para fins didáticos, é apresentada uma maneira de construir um densímetro, aparelho utilizadopara medir a densidade de fluidos. um aparato fácil de ser construído e muito simples de serutilizado. Sua principal vantagem sobre os densímetros que comercialmente encontramos, é a suacapacidade de medir a densidade de quaisquer líquidos, operando em qualquer faixa de densidade. Outra vantagem que apresenta, é a possibilidade de fazer uma medição relativa entre quaisquerlíquidos, não fazendo apenas a medição relativa à densidade da água. Desta maneira, pode-semedir, por exemplo, a densidade do mercúrio em relação ao éter, com este instrumento. Nota-seque, desta maneira, com apenas um instrumento determina-se a densidade de qualquer líquido, nãosendo necessário dispor-se de densímetros que operem em diversas faixas de densidade, como é ocaso dos instrumentos encontrados comercialmente.

  4. Association of the "IUCN vulnerable" spiny rat Clyomys bishopi (Rodentia: Echimyidae) with palm trees and armadillo burrows in southeastern Brazil.

    Science.gov (United States)

    Bueno, Adriana A; Lapenta, Marina J; Oliveira, Fátima; Motta-Junior, José C

    2004-12-01

    The globally vulnerable Clyomys bishopi, a semi-fossorial and colonial rodent, is apparently limited to cerrado (savannah-like vegetation) physiognomies in São Paulo State, Brazil. The aim of the study was to verify whether the presence of C. bishopi is associated to the occurrence of palm trees (Attalea gearensis, Syagrus loefgrenii) and armadillo burrows. Thirty six quadrats were placed in different physiognomies of cerrado vegetation at Itirapina Ecological Station, southeastern Brazil to survey the number of C. bishopi burrows of individuals of palm trees and burrows of armadillos. There was a strong dependence and association between the number of C. bishopi burrows and all measured variables (Contingency tables and Spearman rank correlations). It is suggested that this rodent can be found in great numbers where palm trees are abundant. The use of armadillo burrows possibly makes the movement of the rodents easier inside their own galleries.

  5. Nelson's big horn sheep (Ovis canadensis nelsoni) trample Agassiz's desert tortoise (Gopherus agassizii) burrow at a California wind energy facility

    Science.gov (United States)

    Agha, Mickey; Delaney, David F.; Lovich, Jeffrey E.; Briggs, Jessica; Austin, Meaghan; Price, Steven J.

    2015-01-01

    Research on interactions between Agassiz's desert tortoises (Gopherus agassizii) and ungulates has focused exclusively on the effects of livestock grazing on tortoises and their habitat (Oldemeyer, 1994). For example, during a 1980 study in San Bernardino County, California, 164 desert tortoise burrows were assessed for vulnerability to trampling by domestic sheep (Ovis aries). Herds of grazing sheep damaged 10% and destroyed 4% of the burrows (Nicholson and Humphreys 1981). In addition, a juvenile desert tortoise was trapped and an adult male was blocked from entering a burrow due to trampling by domestic sheep. Another study found that domestic cattle (Bos taurus) trampled active desert tortoise burrows and vegetation surrounding burrows (Avery and Neibergs 1997). Trampling also has negative impacts on diversity of vegetation and intershrub soil crusts in the desert southwest (Webb and Stielstra 1979). Trampling of important food plants and overgrazing has the potential to create competition between desert tortoises and domestic livestock (Berry 1978; Coombs 1979; Webb and Stielstra 1979).

  6. Strong population genetic structure and larval dispersal capability of the burrowing ghost shrimp (Neotrypaea californiensis)

    Science.gov (United States)

    The burrowing ghost shrimp, Neotrypaea californiensis, is a vital member of the estuarine benthic community. Dense populations of shrimp are found in the major estuaries of Washington and Oregon. Our study determines the genetic structure of shrimp populations in order to gain ...

  7. SEASONAL FORAGING BY CHANNEL CATFISH ON TERRESTRIALLY BURROWING CRAYFISH IN A FLOODPLAIN-RIVER ECOSYSTEM

    Science.gov (United States)

    The seasonal use of terrestrially burrowing crayfish as a food item by channel catfish Ictalurus punctatus was studied in channelized and non-channelized sections of the Yockanookany River (Mississippi, USA). During seasonal inundation of the floodplains, the crayfish occupied o...

  8. Burrowing Behavior of a Deposit Feeding Bivalve Predicts Change in Intertidal Ecosystem State

    NARCIS (Netherlands)

    Compton, T.J.; Bodnar, W.; Koolhaas, A.; Dekinga, A.; Holthuijsen, S.; Ten Horn, J.; McSweeney, N.; van Gils, J.A.; Piersma, T,

    2016-01-01

    Behavior has a predictive power that is often underutilized as a tool for signaling ecological change. The burrowing behavior of the deposit feeding bivalve Macoma balthica reflects a typical food-safety trade-off. The choice to live close to the sediment surface comes at a risk of predation and is

  9. Burrowing behavior of a deposit feeding bivalve predicts change in intertidal ecosystem state

    NARCIS (Netherlands)

    Compton, Tanya J.; Bodnar, Wanda; Koolhaas, Anita; Dekinga, Anne; Holthuijsen, Sander; ten Horn, Job; McSweeney, Niamh; van Gils, Jan; Piersma, Theunis

    2016-01-01

    Behavior has a predictive power that is often underutilized as a tool for signaling ecological change. The burrowing behavior of the deposit feeding bivalve Macoma balthica reflects a typical food-safety trade-off. The choice to live close to the sediment surface comes at a risk of predation and is

  10. Gopherus agassizii (desert tortoise) and Crotalus ruber (red diamond rattlesnake). Burrow co-occupancy

    Science.gov (United States)

    Lovich, Jeffrey E.

    2011-01-01

    I observed an adult Desert Tortoise and an adult Red Diamond Rattlesnake (sexes unknown) in a shallow tortoise burrow on 6 January 1997 at a wind energy generation facility near Palm Springs, Riverside Co., California, USA (33.9599°N, 116.6613°W).

  11. The Potential Use of Electricity to Control Burrowing Shrimp in Oyster Aquaculture Beds

    Science.gov (United States)

    Thalassinid shrimp cause significant problems for oyster aquaculture in the Pacific Northwest (USA) where oysters succumb to the physical disruption of the sediment by the burrowing activity of these animals. While electrofishing is a commonly used technique to capture fish and some invertebrates i...

  12. Behaviour and time allocation of the burrowing shrimp Callianassa subterranea (Decapoda, Thalassinidea)

    NARCIS (Netherlands)

    Stamhuis, E.J; Reede-Dekker, T; van Etten, Y; de Wiljes, J.J.; Videler, J.J

    1996-01-01

    The behaviour and allocation of time of the endobenthic shrimp Callianassa subterranea from the central North Sea was studied in the laboratory. Animals were allowed to construct a two-dimensional burrow in large transparent sediment filled cuvettes tailored to their body width. The behaviour of the

  13. Lizard burrows provide thermal refugia for larks in the Arabian desert

    NARCIS (Netherlands)

    Williams, JB; Tieleman, BI; Shobrak, M

    1999-01-01

    A common perception is that desert birds experience greater extremes of heat and aridity than their mammalian counterparts, in part, because birds do not use burrows as a refuge from the desert environment. We report observations of Dunn's Larks (Eremalauda dunni), Bar-tailed Desert Larks (Ammomanes

  14. Burrowing and foraging activity of marsh crabs under different inundation regimes

    Science.gov (United States)

    New England salt marshes are susceptible to degradation and habitat loss as a result of increased periods of inundation as sea levels rise. Increased inundation may exacerbate marsh degradation that can result from crab burrowing and foraging. Most studies to date have focused on...

  15. First implementation of burrowing motions in dual-reciprocating drilling using an integrated actuation mechanism

    Science.gov (United States)

    Pitcher, Craig; Gao, Yang

    2017-03-01

    The dual-reciprocating drill (DRD) is a biologically-inspired low-mass alternative to traditional drilling techniques, using backwards-facing teethed halves to grip the surrounding substrate, generating a traction force that reduces the required overhead penetration force. Previous experiments using a proof-of-concept test bench have provided evidence as to the significant role of sideways movements and lateral forces in improving drilling performance. The system is also progressing to a first system prototype concept, in which an actuation mechanism is integrated within the drill heads. To experimentally determine the effect of lateral motions, a new internal actuation mechanism was developed to allow the inclusion of controlled sideways movements, resulting in the creation of the circular and diagonal burrowing motions. This paper presents an investigation into the performance of the reciprocation and burrowing motions by testing them in a planetary regolith simulant. Analysis of force sensor measurements has shown a relationship between the penetration and traction forces and the internal friction of the mechanism and depth achieved. These tests have also experimentally demonstrated the benefit of lateral motions in drilling performance, with both the burrowing mechanisms and drilling tests performed at an angle able to penetrate further than traditional vertical reciprocation, leading to the proposition of new burrowing and diagonal drilling mechanics. From this, a new fully integrated system prototype can be developed which incorporates lateral motions that can optimise the drilling performance.

  16. Simultaneous collection of body temperature and activity data in burrowing mammals : a new technique

    NARCIS (Netherlands)

    Long, Ryan A.; Hut, Roelof A.; Barnes, Brian M.

    2007-01-01

    Integrating physiological and behavioral observations into ecological field studies of animals can provide novel insights into relationships among animal behavior, physiology, and ecology. We describe and evaluate a new technique for simultaneously collecting body temperature (T-b) and burrow use da

  17. Rabbits, refuges and resources : how foraging of herbivores is affected by living in burrows

    NARCIS (Netherlands)

    Dekker, J.J.A.

    2007-01-01

    Small herbivores such as rabbits, pika and marmots create spatial patterns in vegetation around their burrows by grazing. This PhD thesis focuses on these refuge-living herbivores.By performing experiments with rabbits, he showed that looking for predators causes the spatial patter

  18. Burrowing dragonfly larvae as biosentinels of methylmercury in freshwater food webs.

    Science.gov (United States)

    Haro, Roger J; Bailey, Sean W; Northwick, Reid M; Rolfhus, Kristofer R; Sandheinrich, Mark B; Wiener, James G

    2013-08-06

    We assessed the utility of larval burrowing dragonflies (Odonata: Anisoptera: Gomphidae) as biosentinels of methylmercury (MeHg) contamination. Gomphids were the most abundant family of dragonflies sampled during 2008-2010 from 17 lakes in four national parks of the northwestern Laurentian Great Lakes region. Ten species of burrowing gomphids were sampled; 13 lakes contained 3 or more species, and 2 species of Gomphus co-occurred in 12 lakes. Most of the total Hg (THg) in whole, late-instar larvae was MeHg, with mean percent MeHg exceeding 60% in 16 lakes. Mean MeHg in larvae of a given species varied greatly among lakes, ranging from 4 to 109 ng g(-1) dry weight. Methylmercury levels in larvae, however, were much less variable within a given lake and species. The mean concentration of MeHg in burrowing gomphids was positively correlated with mean MeHg concentration in unfiltered lake water. Mean concentrations of THg and MeHg in multispecies assemblages of Gomphus were also positively correlated with mean THg in coexisting prey fish and game fishes. We recommend-and provide guidance on-the application of burrowing gomphids as biosentinels of MeHg contamination, which can extend the bioassessment of MeHg to fishless fresh waters.

  19. Dens evaginatus and dens invaginatus in a double tooth: A rare case report

    Directory of Open Access Journals (Sweden)

    Gaurav Sharma

    2015-01-01

    Full Text Available The presence of dens invaginatus (DI and dens evaginatus (DE on same tooth is a rare phenomenon. However, when these dental anomalies occur on a double tooth, it becomes an extremely rare phenomenon. The authors report a rare case of DI and DE on fused permanent maxillary central incisor with supernumerary tooth in a 40-year-old male. The present article also focuses on the differentiating fusion from gemination and also reviews preventive and management strategies for tooth with complex dental anatomy.

  20. Effect of mangrove restoration on crab burrow density in Luoyangjiang Estuary, China

    Directory of Open Access Journals (Sweden)

    Wei Li

    2015-07-01

    Full Text Available Background Mangrove restoration seeks to restore or rebuild degraded mangrove systems. The methods of mangrove restoration include ecological projects and restoration-oriented technologies, the latter of which are designed to restore the structure, processes as well as related physical, chemical and biological characteristics of wetlands and to ensure the provision of ecosystem services. As important components of mangrove ecosystem, benthic organisms and crabs play a key role in nutrient cycling. In addition, mangrove restoration, such as vegetation restoration measures, can lead to changes in the benthic faunal communities. This study investigates whether the presence of different mangrove species, age and canopy cover of mangrove communities affect the density of crab burrows. Methods The Luoyangjiang Estuary, in the southeast of Fujian Province, was selected as our research area. A survey, covering 14 sites, was conducted to investigate the impacts of mangrove restoration on the density of crab burrows in four rehabilitated forests with different stand ages and canopy. Results It was found that differences in vegetation types had a large impact on crab density and that the density of crab burrows was lower on exposed beaches (non-mangrove than under mature Kandelia candel, Aegiceras corniculatum and Avicennia marina communities. In general, the amount of leaf litter and debris on mangrove mudflats was greater than on the beaches as food sources for crabs. Two-factor analysis of variance (ANOVA shows that changes in mangrove species and age since restoration had different effects on crab burrow density. The effect of canopy cover was highly significant on crab burrow density. Conclusions The results suggest that in the process of mangrove restoration the combined effects of mangrove stand age, canopy cover and other factors should be taken into account. This study further supports the findings of the future scientific research and practice on

  1. The effect of mayfly (Hexagenia spp.) burrowing activity on sediment oxygen demand in western Lake Erie

    Science.gov (United States)

    Edwards, William J.; Soster, Frederick M.; Matisoff, Gerald; Schloesser, Donald W.

    2009-01-01

    Previous studies support the hypothesis that large numbers of infaunal burrow-irrigating organisms in the western basin of Lake Erie may increase significantly the sediment oxygen demand, thus enhancing the rate of hypolimnetic oxygen depletion. We conducted laboratory experiments to quantify burrow oxygen dynamics and increased oxygen demand resulting from burrow irrigation using two different year classes of Hexagenia spp. nymphs from western Lake Erie during summer, 2006. Using oxygen microelectrodes and hot film anemometry, we simultaneously determined oxygen concentrations and burrow water flow velocities. Burrow oxygen depletion rates ranged from 21.7 mg/nymph/mo for 15 mm nymphs at 23 °C to 240.7 mg/nymph/mo for 23 mm nymphs at 13 °C. Sealed microcosm experiments demonstrated that mayflies increase the rate of oxygen depletion by 2-5 times that of controls, depending on size of nymph and water temperature, with colder waters having greater impact. At natural population densities, nymph pumping activity increased total sediment oxygen demand 0.3-2.5 times compared to sediments with no mayflies and accounted for 22-71% of the total sediment oxygen demand. Extrapolating laboratory results to the natural system suggest that Hexagenia spp. populations may exert a significant control on oxygen depletion during intermittent stratification. This finding may help explain some of the fluctuations in Hexagenia spp. population densities in western Lake Erie and suggests that mayflies, by causing their own population collapse irrespective of other environmental conditions, may need longer term averages when used as a bio-indicator of the success of pollution-abatement programs in western Lake Erie and possibly throughout the Great Lakes.

  2. Finansiell risikostyring i den amerikanske flybransjen

    OpenAIRE

    Orleanski, Anna Karolina; Schulte, André Evensen

    2010-01-01

    Denne oppgaven tar for seg finansiell risikostyring i den amerikanske flybransjen, med hovedfokus på sikring av drivstoff. Drivstoff har historisk stått for 20-30 prosent av flyselskapenes driftskostnader, og høy volatilitet i drivstoffprisen gjør at mange sikrer råvaren. Vi undersøker om finansiell risikostyring bidrar til økt selskapsverdi, med hovedfokus på drivstoffprissikring, men inkluderer også valuta- og rentesikring der det er mulig. Studien baseres på offentlig selskapsinformasjon f...

  3. Zu den on Emona und Ljubljana

    Directory of Open Access Journals (Sweden)

    Jaroslav Šašel

    1984-12-01

    Full Text Available Die Bildungssilbe -ona wurde in übernommenen ON von den Slawen regelmässig auf -in umgebildet (Salona-Solin. Dieser Gruppe wird vom Autor auch die Form Atamine beigezählt (für Emona, Anon. Ravenn. 4.20, die infolge einer Diskontinuität in Vergessenheit geriet. Im Bereich derselben Siedlungsstelle taucht später der ON Ljubljana auf, dessen Bildungssilbe -ana (wie in ON Fažana, Sežana auf lokales Bestehen eines sprachlich vorslawischen Elements hindeutet. Lit. und Beispiele s. im Text oben.

  4. BURROW ARCHITECTURE OF RED GHOST CRAB OCYPODE MACROCERA (H. MILNE-EDWARDS, 1852 : A CASE STUDY IN INDIAN SUNDARBANS

    Directory of Open Access Journals (Sweden)

    Sourabh Kumar Dubey

    2013-12-01

    Full Text Available A study on burrow architecture and burrow morphology of the red ghost crab (Ocypode macrocera was carried out at the southern proximity of the Sagar island (21°37.973' N, to E 88° 04.195', western sector of Indian Sundarbans that faces the regular tidal influences of Bay of Bengal. Ocypode macrocera constructs burrows that are highly species specific and used by single individual. Four types of burrow patterns were observed like ‘I’, ‘J’ ‘U’ and ‘semi-U’ type with different sizes as revealed by POP casting. Important physic-chemical parameters like air temperature, temperature and salinity of the water were significantly varied (P < 0.05 throughout seasons in the Ocypode zone. Burrow sand column temperature were also significantly varied from ambient air temperature thus exhibiting preference for cooler subterranean residential compartment. The digging behaviour of Ocypodes enhances oxygenation in the ground soil and facilitates decomposition of organic materials, nutrient recycling, entrapping the sediments and mangrove seedlings and helps the process of bioturbation. As per the preliminary observations it was suggested that burrow shape is directly related to tidal action and metabolic activities of the crab are strongly correlated with burrow microenvironment. They are adapted to the different sediment conditions, tidal fluctuations, varying salinity gradients, air and water temperatures and other environmental fluctuations.

  5. Evaluation of insecticide impregnated baits for control of mosquito larvae in land crab burrows on French Polynesian atolls.

    Science.gov (United States)

    Lardeux, Frederic; Sechan, Yves; Faaruia, Marc

    2002-07-01

    Land crab burrows are larval mosquito habitats of major significance in the Pacific region. They are constituted by a sinuous tunnel leading to a chamber in contact with the water table, where mosquito larvae proliferate. Controlling larvae in these sites is difficult, because the configuration of burrows prevents the use of standard techniques. An experiment was carried out in French Polynesia to control Aedes polynesiensis Marks and Culex spp. breeding in burrows of the land crab Cardisoma carnifex (Herbst). The technique was based on the crab's behavior, which involves the crab carrying food into its burrow. It was shown that appetizing baits impregnated with an insecticide were carried by crabs into the flooded chamber of their burrows. A field treatment of burrows was carried out by sowing insecticide impregnated baits on the ground. The treatment coverage was almost perfect and the easy implementation of the technique enabled large areas to be treated in a short time. The bait was developed by compacting various flours, which easily incorporate a large variety of insecticide formulations. Although the baits can be easily stocked, a reliable insecticide is still to be found. The results indicate that our technique could be a method of choice for treating crab burrows.

  6. Mesozoic dinosaurs from Brazil and their biogeographic implications

    Directory of Open Access Journals (Sweden)

    Jonathas S. Bittencourt

    2011-03-01

    Full Text Available The record of dinosaur body-fossils in the Brazilian Mesozoic is restricted to the Triassic of Rio Grande do Sul and Cretaceous of various parts of the country. This includes 21 named species, two of which were regarded as nomina dubia, and 19 consensually assigned to Dinosauria. Additional eight supraspecific taxa have been identified based on fragmentary specimens and numerous dinosaur footprints known in Brazil. In fact, most Brazilian specimens related to dinosaurs are composed of isolated teeth and vertebrae. Despite the increase of fieldwork during the last decade, there are still no dinosaur body-fossils of Jurassic age and the evidence of ornithischians in Brazil is very limited. Dinosaur faunas from this country are generally correlated with those from other parts of Gondwana throughout the Mesozoic. During the Late Triassic, there is a close correspondence to Argentina and other south-Pangaea areas. Mid-Cretaceous faunas of northeastern Brazil resemble those of coeval deposits of North Africa and Argentina. Southern hemisphere spinosaurids are restricted to Africa and Brazil, whereas abelisaurids are still unknown in the Early Cretaceous of the latter. Late Cretaceous dinosaur assemblages of south-central Brazil are endemic only to genus or, more conspicuously, to species level, sharing closely related taxa with Argentina, Madagascar, Indo-Pakistan and, to a lesser degree, continental Africa.O registro osteológico de dinossauros no Mesozóico brasileiro está restrito a rochas triássicas do Rio Grande do Sul e estratos cretáceos de várias partes do país. Isto inclui 21 espécies nominais, sendo duas referidas como nomina dubia, e 19 consensualmente classificadas como dinossauros. Oito táxons supraespecíficos adicionais baseados em material fragmentado e diversas pegadas são conhecidos no Brasil. De fato, a maior parte dos espécimes é composta de dentes isolados e vértebras. Apesar do aumento em trabalhos de campo na última

  7. Control of multicellular development by the physically interacting deneddylases DEN1/DenA and COP9 signalosome.

    Directory of Open Access Journals (Sweden)

    Martin Christmann

    Full Text Available Deneddylases remove the ubiquitin-like protein Nedd8 from modified proteins. An increased deneddylase activity has been associated with various human cancers. In contrast, we show here that a mutant strain of the model fungus Aspergillus nidulans deficient in two deneddylases is viable but can only grow as a filament and is highly impaired for multicellular development. The DEN1/DenA and the COP9 signalosome (CSN deneddylases physically interact in A. nidulans as well as in human cells, and CSN targets DEN1/DenA for protein degradation. Fungal development responds to light and requires both deneddylases for an appropriate light reaction. In contrast to CSN, which is necessary for sexual development, DEN1/DenA is required for asexual development. The CSN-DEN1/DenA interaction that affects DEN1/DenA protein levels presumably balances cellular deneddylase activity. A deneddylase disequilibrium impairs multicellular development and suggests that control of deneddylase activity is important for multicellular development.

  8. Deccan volcanism, the KT mass extinction and dinosaurs

    Indian Academy of Sciences (India)

    G Keller; A Sahni; S Bajpai

    2010-03-01

    Recent advances in Deccan volcanic studies indicate three volcanic phases with the phase-1 at 67.5 Ma followed by a 2 m.y. period of quiescence. Phase-2 marks the main Deccan volcanic eruptions in Chron 29r near the end of the Maastrichtian and accounts for ∼80% of the entire 3500 m thick Deccan lava pile. At least four of the world’s longest lava flows spanning 1000 km across India and out into the Gulf of Bengal mark phase-2. The final phase-3 was smaller, coincided with the early Danian Chron 29n and also witnessed several of the longest lava flows. The KT boundary and mass extinction was first discovered based on planktic foraminifera from shallow marine intertrappean sediments exposed in Rajahmundry quarries between the longest lava flows of the main volcanic phase-2 and smaller phase-3. At this locality early Danian (zone P1a) planktic foraminiferal assemblages directly overlie the top of phase-2 eruptions and indicate that the masse extinction coincided with the end of this volcanic phase. Planktic foraminiferal assemblages also mark the KT boundary in intertrappean sediments at Jhilmili, Chhindwara, where freshwater to estuarine conditions prevailed during the early Danian and indicate the presence of a marine seaway across India at KT time. Dinosaur bones, nesting sites with complete eggs and abundant eggshells are known from central India surrounding the hypothesized seaway through the Narmada-Tapti rift zone. A Maastrichtian age is generally assigned to these dinosaur remains. Age control may now be improved based on marine microfossils from sequences deposited in the seaway and correlating these strata to nearby terrestrial sequences with dinosaur remains.

  9. Adaptive radiation of multituberculate mammals before the extinction of dinosaurs.

    Science.gov (United States)

    Wilson, Gregory P; Evans, Alistair R; Corfe, Ian J; Smits, Peter D; Fortelius, Mikael; Jernvall, Jukka

    2012-03-14

    The Cretaceous-Paleogene mass extinction approximately 66 million years ago is conventionally thought to have been a turning point in mammalian evolution. Prior to that event and for the first two-thirds of their evolutionary history, mammals were mostly confined to roles as generalized, small-bodied, nocturnal insectivores, presumably under selection pressures from dinosaurs. Release from these pressures, by extinction of non-avian dinosaurs at the Cretaceous-Paleogene boundary, triggered ecological diversification of mammals. Although recent individual fossil discoveries have shown that some mammalian lineages diversified ecologically during the Mesozoic era, comprehensive ecological analyses of mammalian groups crossing the Cretaceous-Paleogene boundary are lacking. Such analyses are needed because diversification analyses of living taxa allow only indirect inferences of past ecosystems. Here we show that in arguably the most evolutionarily successful clade of Mesozoic mammals, the Multituberculata, an adaptive radiation began at least 20 million years before the extinction of non-avian dinosaurs and continued across the Cretaceous-Paleogene boundary. Disparity in dental complexity, which relates to the range of diets, rose sharply in step with generic richness and disparity in body size. Moreover, maximum dental complexity and body size demonstrate an adaptive shift towards increased herbivory. This dietary expansion tracked the ecological rise of angiosperms and suggests that the resources that were available to multituberculates were relatively unaffected by the Cretaceous-Paleogene mass extinction. Taken together, our results indicate that mammals were able to take advantage of new ecological opportunities in the Mesozoic and that at least some of these opportunities persisted through the Cretaceous-Paleogene mass extinction. Similar broad-scale ecomorphological inventories of other radiations may help to constrain the possible causes of mass extinctions.

  10. Continental Ecosystem Instability During the Late Triassic Rise of Dinosaurs

    Science.gov (United States)

    Whiteside, J. H.; Dunlavey, M.; Lindström, S.; Irmis, R. B.; Kasprak, A. H.; Glasspool, I.; Nesbitt, S.; Smith, N.; Turner, A.

    2012-12-01

    Our assessment of the Earth system response to future global climate change requires the characterization of feedbacks that occur at temperatures significantly warmer than modern. Patterns derived from hothouse intervals in Earth's past can inform process-based models to better understand and predict such feedbacks. pCO2 values exceeded 1000 ppm during the Late Triassic (~235 million to 201.5 million years ago), one of the warmest - and one of the most climatically dynamic - intervals in Earth history. This long period of warmth saw rare and species-poor assemblages of early dinosaurs and their relatives at low-paleolatitudes. Here we present new records of palynology, charcoal, polycyclic aromatic hydrocarbon (PAH) biomarkers of regional wildfires, and the bulk carbon isotopic composition of organic matter (δ13Corg) from fluvial and overbank sediments of the Chinle Formation of the Chama Basin in north-central New Mexico from low paleolatitude Pangea. These data illuminate the climatic and ecological drivers of low dinosaur diversity. Our data suggest that strongly fluctuating but generally very hot and periodically arid environmental conditions prevailed at low paleolatitudes in the Late Triassic. Strong variations in δ13Corg and xerophytic palynomorph abundance are highly correlated, suggesting these proxies responded to fluctuating arid conditions with intermittent wildfires, some burning at temperatures reaching at least 680°C. The abundant, reliable food source required by an extensive, diverse community of large-bodied, herbivorous, fast-growing tachymetabolic dinosaurs did not develop until climatic changes in the Early Jurassic. Despite this, the basic structure of this pseudosuchian archosaur-dominated community remained stable over ~10-15 million years.

  11. Deccan volcanism, the KT mass extinction and dinosaurs

    Indian Academy of Sciences (India)

    G Keller; A Sahni; S Bajpai

    2009-11-01

    Recent advances in Deccan volcanic studies indicate three volcanic phases with the phase-1 at 67.5 Ma followed by a 2 m.y. period of quiescence. Phase-2 marks the main Deccan volcanic eruptions in Chron 29r near the end of the Maastrichtian and accounts for ∼80% of the entire 3500 m thick Deccan lava pile. At least four of the world’s longest lava flows spanning 1000 km across India and out into the Gulf of Bengal mark phase-2. The final phase-3 was smaller, coincided with the early Danian Chron 29n and also witnessed several of the longest lava flows. The KT boundary and mass extinction was first discovered based on planktic foraminifera from shallow marine intertrappean sediments exposed in Rajahmundry quarries between the longest lava flows of the main volcanic phase-2 and smaller phase-3. At this locality early Danian (zone P1a) planktic foraminiferal assemblages directly overlie the top of phase-2 eruptions and indicate that the masse extinction coincided with the end of this volcanic phase. Planktic foraminiferal assemblages also mark the KT boundary in intertrappean sediments at Jhilmili, Chhindwara, where freshwater to estuarine conditions prevailed during the early Danian and indicate the presence of a marine seaway across India at KT time. Dinosaur bones, nesting sites with complete eggs and abundant eggshells are known from central India surrounding the hypothesized seaway through the Narmada-Tapti rift zone. A Maastrichtian age is generally assigned to these dinosaur remains. Age control may now be improved based on marine microfossils from sequences deposited in the seaway and correlating these strata to nearby terrestrial sequences with dinosaur remains.

  12. Den danske FN-bataljon i den ikke anerkendte stat Republika Srpska Krajina, 1992-1995

    DEFF Research Database (Denmark)

    Brink Rasmussen, Jakob

    2014-01-01

    Artiklen beskriver og analyserer en dansk FN-styrkes erfaringer med fredsbevarende operationer i forbindelse med Kroatiens løsrivelse fra det tidligere Jugoslavien. Den følger de næste års konflikt med de etniske serbere, som i perioden 1992-1995 forsøgte at opbygge og fastholde deres egen stat i...

  13. Endolithic fungi: A possible killer for the mass extinc-tion of Cretaceous dinosaurs

    Institute of Scientific and Technical Information of China (English)

    GONG YiMing; XU Ran; HU Bi

    2008-01-01

    Mycelium-like structures found under ESEM within radial sections of fragmental dinosaur eggshells would be the endolithic fungi coexistent with dinosaur eggs in the upper part of the Late Cretaceous Hugang Formation from the Wenjiaping section of Wenxian, Danjiangkou, northwestern Hubei, Central China. The endolithic fungi selectively occurred in the bad biomineral zone within the columnar layer of the eggshells, where the crowded endolithic fungi penetrated the columnar layer at near-vertical or near-horizontal angles. The endolithic fungi are needle-like, ribbon-like and silk-like, and 5-18 μm long, 0.3-0.5 μm wide at their base, with pointed tip, and are unbranched. The hyphae are mainly composed of oxygen, carbon and calcium, and are with minor sodium, potassium, chlorine and sulfur. The en-dolithic fungi and host have the same characters in lithification, fracture and main chemical composi-tion. We suggested that the episode endolithic fungi invading dinosaur eggs may have taken place in the interval between after formation of dinosaur eggshells and before their petrifaction and that dino-saur eggs invaded by endolithic fungi would not be normally incubated or would only be incubated into venerable and pathologic baby dinosaurs to be easily to aborted and contributed to the mass extinction of the dinosaurs at the end of Cretaceous.

  14. The history of dinosaur footprint discoveries in Wyoming with emphasis on the Bighorn basin

    Science.gov (United States)

    Kvale, E.P.; Mickelson, D.L.; Hasiotis, S.T.; Johnson, G.D.

    2003-01-01

    Dinosaur traces are well known from the western United States in the Colorado Plateau region (Utah, Colorado, New Mexico, and Arizona). Utah contains the greatest abundance of known and documented dinosaur footprints and trackways. Far less well known, however, is the occurrence and distribution of dinosaur footprint-bearing horizons in Wyoming. Scientific studies over the past 10 years have shown that three of the four Middle and Upper Jurassic formations in northern Wyoming contain dinosaur footprints. Two of the footprint-bearing horizons are located in geologic intervals that were once thought to have been deposited in offshore to nearshore marine settings and represent rare North American examples of Middle Jurassic (Bajocian and Bathonian) dinosaur remains. Some of these new Wyoming sites can be correlated to known dinosaur footprint-bearing horizons or intervals in Utah. Wyoming has a great potential for additional discoveries of new dinosaur footprint-bearing horizons, and further prospecting and study is warranted and will ultimately lead to a much better understanding of the geographic distribution and behavior of the potential footprint-makers. ?? Taylor and Francis Inc.

  15. Endolithic fungi: A possible killer for the mass extinction of Cretaceous dinosaurs

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Mycelium-like structures found under ESEM within radial sections of fragmental dinosaur eggshells would be the endolithic fungi coexistent with dinosaur eggs in the upper part of the Late Cretaceous Hugang Formation from the Wenjiaping section of Wenxian, Danjiangkou, northwestern Hubei, Central China. The endolithic fungi selectively occurred in the bad biomineral zone within the columnar layer of the eggshells, where the crowded endolithic fungi penetrated the columnar layer at near-vertical or near-horizontal angles. The endolithic fungi are needle-like, ribbon-like and silk-like, and 5-18 μm long, 0.3-0.5 μm wide at their base, with pointed tip, and are unbranched. The hyphae are mainly composed of oxygen, carbon and calcium, and are with minor sodium, potassium, chlorine and sulfur. The en-dolithic fungi and host have the same characters in lithification, fracture and main chemical composi-tion. We suggested that the episode endolithic fungi invading dinosaur eggs may have taken place in the interval between after formation of dinosaur eggshells and before their petrifaction and that dino-saur eggs invaded by endolithic fungi would not be normally incubated or would only be incubated into venerable and pathologic baby dinosaurs to be easily to aborted and contributed to the mass extinction of the dinosaurs at the end of Cretaceous.

  16. Dinosaur egg deposits in the Cretaceous Gyeongsang Supergroup, Korea: Diversity and paleobiological implications

    Science.gov (United States)

    Paik, In Sung; Kim, Hyun Joo; Huh, Min

    2012-08-01

    The taphonomy and depositional environments of dinosaur-egg-bearing deposits in the Cretaceous Gyeongsang Basin, Korea, are described and their paleobiological implications are discussed in the context of global geographic occurrences, geological ages, paleoenvironments, and lithology. The general depositional environment of dinosaur egg deposits in the Gyeongsang Supergroup is interpreted as dry floodplains with a semi-arid climate and intermittent volcanic activity. The diverse floodplain paleoenvironments include fluvial plains with meandering rivers to alluvial plains with episodic sheet-flooding. Both global and Korean dinosaur-egg-bearing deposits are generally restricted to the Late Cretaceous, a phenomenon for which two possible explanations are proposed. The first possible explanation for the temporal limitation of dinosaur egg preservation involves the appearance of angiosperms in the Late Jurassic, the Late Cretaceous ecological dispersion of angiosperm trees into swamps and floodplains, and the attendant change in herbivorous dinosaurs' diets. The second possible reason is related to nesting behavior in the Cretaceous. By contrast to the temporally limited occurrence of dinosaur eggs, paleoenvironments of nesting areas are diverse, ranging from inland areas to coastal areas. These hypotheses may provide new directions for the study and understanding of dinosaur egg distribution in the context of geologic time.

  17. Eggshell Porosity Provides Insight on Evolution of Nesting in Dinosaurs.

    Science.gov (United States)

    Tanaka, Kohei; Zelenitsky, Darla K; Therrien, François

    2015-01-01

    Knowledge about the types of nests built by dinosaurs can provide insight into the evolution of nesting and reproductive behaviors among archosaurs. However, the low preservation potential of their nesting materials and nesting structures means that most information can only be gleaned indirectly through comparison with extant archosaurs. Two general nest types are recognized among living archosaurs: 1) covered nests, in which eggs are incubated while fully covered by nesting material (as in crocodylians and megapodes), and 2) open nests, in which eggs are exposed in the nest and brooded (as in most birds). Previously, dinosaur nest types had been inferred by estimating the water vapor conductance (i.e., diffusive capacity) of their eggs, based on the premise that high conductance corresponds to covered nests and low conductance to open nests. However, a lack of statistical rigor and inconsistencies in this method render its application problematic and its validity questionable. As an alternative we propose a statistically rigorous approach to infer nest type based on large datasets of eggshell porosity and egg mass compiled for over 120 extant archosaur species and 29 archosaur extinct taxa/ootaxa. The presence of a strong correlation between eggshell porosity and nest type among extant archosaurs indicates that eggshell porosity can be used as a proxy for nest type, and thus discriminant analyses can help predict nest type in extinct taxa. Our results suggest that: 1) covered nests are likely the primitive condition for dinosaurs (and probably archosaurs), and 2) open nests first evolved among non-avian theropods more derived than Lourinhanosaurus and were likely widespread in non-avian maniraptorans, well before the appearance of birds. Although taphonomic evidence suggests that basal open nesters (i.e., oviraptorosaurs and troodontids) were potentially the first dinosaurs to brood their clutches, they still partially buried their eggs in sediment. Open nests

  18. Texture analyses of Sauropod dinosaur bones from Tendaguru

    Energy Technology Data Exchange (ETDEWEB)

    Pyzalla, A.R. [TU Wien, Institute of Material Science and Technology, Karlsplatz 13-308, A-1040 Vienna (Austria) and MPI fuer Eisenforschung GmbH, Max-Planck-Str. 1, D-40237 Duesseldorf (Germany)]. E-mail: pyzalla@mpie.de; Sander, P.M. [University of Bonn, Institute of Palaeontology, Nusseallee, D-53115 Bonn (Germany); Hansen, A. [TU Clausthal, Institute of Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processingnd GKSS Research Centre Geesthacht GmbH, Geesthacht, Max-Planck-Str.1, D-21502 Geesthacht (Germany); Ferreyro, R. [TU Wien, Institute of Material Science and Technology, Karlsplatz 13-308, A-1040 Vienna (Austria); Yi, S.-B. [TU Clausthal, Institute of Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processingnd GKSS Research Centre Geesthacht GmbH, Geesthacht, Max-Planck-Str.1, D-21502 Geesthacht (Germany); MPI fuer Eisenforschung GmbH, Max-Planck-Str. 1, D-40237 Duesseldorf (Germany); Stempniewicz, M. [TU Wien, Institute of Material Science and Technology, Karlsplatz 13-308, A-1040 Vienna (Austria); Brokmeier, H.-G. [TU Clausthal, Institute of Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processingnd GKSS Research Centre Geesthacht GmbH, Geesthacht, Max-Planck-Str.1, D-21502 Geesthacht (Germany)

    2006-11-10

    The apatite texture of fossil Brachiosaurus brancai and Barosaurus africanus sauropod bones from the excavation site at Tendaguru, Tanzania, was characterized by neutron diffraction pole figures. The results obtained reveal predominantly <0 0 0 1>-fibre textures of the apatite; the fibre direction coincides with the longitudinal direction of the long bones of the skeletons. Neutron pole figures further indicate that other texture types may also be present. Texture strength is similar to dinosaur tendons and contemporary turkey tendon studied by others. Variations of texture strength across the bone wall cross-sections are not significantly large.

  19. Why freshwater organisms survived the asteroid that killed the dinosaurs

    Science.gov (United States)

    Schultz, Colin

    2013-08-01

    Roughly 65.5 million years ago, a massive asteroid smashed into present-day Chicxulub, Mexico. The impact set fire to Earth's surface. Dust and ash darkened the sky, sending the planet into an "impact winter" that lasted months to years and caused the extinction of nonavian dinosaurs and half of ocean-dwelling species. However, life in inland freshwater ecosystems largely escaped this fate. To try to understand why freshwater organisms held on while ocean life failed, Robertson et al. surveyed relevant research to understand how the mechanisms of extinction would have operated differently in the two environments.

  20. Treatment of black-tailed prairie dog burrows with deltamethrin to control fleas (Insecta: Siphonaptera) and plague.

    Science.gov (United States)

    Seery, David B; Biggins, Dean E; Montenieri, John A; Enscore, Russell E; Tanda, Dale T; Gage, Kenneth L

    2003-09-01

    Burrows within black-tailed prairie dog (Cynomys ludovicianus) colonies on the Rocky Mountain Arsenal National Wildlife Refuge, Colorado, were dusted with deltamethrin insecticide to reduce flea (Insecta: Siphonaptera) abundance. Flea populations were monitored pre- and posttreatment by combing prairie dogs and collecting fleas from burrows. A single application of deltamethrin significantly reduced populations of the plague vector Oropsylla hirsuta, and other flea species on prairie dogs and in prairie dog burrows for at least 84 d. A plague epizootic on the Rocky Mountain Arsenal National Wildlife Refuge caused high mortality of prairie dogs on some untreated colonies, but did not appear to affect nearby colonies dusted with deltamethrin.

  1. Ecological interactions in dinosaur communities: influences of small offspring and complex ontogenetic life histories.

    Science.gov (United States)

    Codron, Daryl; Carbone, Chris; Clauss, Marcus

    2013-01-01

    Because egg-laying meant that even the largest dinosaurs gave birth to very small offspring, they had to pass through multiple ontogenetic life stages to adulthood. Dinosaurs' successors as the dominant terrestrial vertebrate life form, the mammals, give birth to live young, and have much larger offspring and less complex ontogenetic histories. The larger number of juveniles in dinosaur as compared to mammal ecosystems represents both a greater diversity of food available to predators, and competitors for similar-sized individuals of sympatric species. Models of population abundances across different-sized species of dinosaurs and mammals, based on simulated ecological life tables, are employed to investigate how differences in predation and competition pressure influenced dinosaur communities. Higher small- to medium-sized prey availability leads to a normal body mass-species richness (M-S) distribution of carnivorous dinosaurs (as found in the theropod fossil record), in contrast to the right-skewed M-S distribution of carnivorous mammals (as found living members of the order Carnivora). Higher levels of interspecific competition leads to a left-skewed M-S distribution in herbivorous dinosaurs (as found in sauropods and ornithopods), in contrast to the normal M-S distribution of large herbivorous mammals. Thus, our models suggest that differences in reproductive strategy, and consequently ontogeny, explain observed differences in community structure between dinosaur and mammal faunas. Models also show that the largest dinosaurian predators could have subsisted on similar-sized prey by including younger life stages of the largest herbivore species, but that large predators likely avoided prey much smaller than themselves because, despite predicted higher abundances of smaller than larger-bodied prey, contributions of small prey to biomass intake would be insufficient to satisfy meat requirements. A lack of large carnivores feeding on small prey exists in mammals

  2. Digital kommunikation med den offentlige sektor

    DEFF Research Database (Denmark)

    Berger, Jesper; Andersen, Kim Normann

    2013-01-01

    til. I denne undersøgelse sættes der fokus på myndighedernes besvarelse af den digitale post. Digital post blev bl.a. etableret som et alternativ til almindelig e-mail for at det offentlige kan kommunikere med borgere og virksomheder på en sikker måde, dvs. uden at uvedkommende kan få adgang til...... følsomme oplysninger. Fokus for undersøgelsen er hvordan håndterer myndighederne besvarelserne i den digitale postkasse: svarer de på digital post og e-mail, hvor hurtigt svarer de og er svarene brugbare? Undersøgelsen medtager myndighedernes besvarelse af digital post og e-mail, dels for at kunne...... sammenligne de to digitale kanaler og for at kunne sammenligne med en tidligere undersøgelse af digital kommunikation med det offentlige. Herudover er der tidligere gennemført en undersøgelse af e-mail svar og svartider i New Zealand og Australien. De danske resultater fra e-mail undersøgelsen, men ikke...

  3. Digital kommunikation med den offentlige sektor

    DEFF Research Database (Denmark)

    Berger, Jesper Bull; Andersen, Kim Normann

    til. I denne undersøgelse sættes der fokus på myndighedernes besvarelse af den digitale post. Digital post blev bl.a. etableret som et alternativ til almindelig e-mail for at det offentlige kan kommunikere med borgere og virksomheder på en sikker måde, dvs. uden at uvedkommende kan få adgang til...... følsomme oplysninger. Fokus for undersøgelsen er hvordan håndterer myndighederne besvarelserne i den digitale postkasse: svarer de på digital post og e-mail, hvor hurtigt svarer de og er svarene brugbare? Undersøgelsen medtager myndighedernes besvarelse af digital post og e-mail, dels for at kunne...... sammenligne de to digitale kanaler og for at kunne sammenligne med en tidligere undersøgelse af digital kommunikation med det offentlige. Herudover er der tidligere gennemført en undersøgelse af e-mail svar og svartider i New Zealand og Australien. De danske resultater fra e-mail undersøgelsen, men ikke...

  4. Digital kommunikation med den offentlige sektor

    DEFF Research Database (Denmark)

    Berger, Jesper Bull; Andersen, Kim Normann

    digital postkasse, som borgerne kunne skrive til. I denne undersøgelse sættes der fokus på myndighedernes besvarelse af den digitale post. Digital post blev bl.a. etableret som et alternativ til almindelig e-mail for at det offentlige kan kommunikere med borgere og virksomheder på en sikker måde, dvs....... uden at uvedkommende kan få adgang til følsomme oplysninger. Fokus for undersøgelsen er hvordan håndterer myndighederne besvarelserne i den digitale postkasse: svarer de på digital post og e-mail, hvor hurtigt svarer de og er svarene brugbare? Vi har også undersøgt besvarelse af e-mail, dels...... for at kunne sammenligne de to digitale kanaler og for at kunne sammenligne med en tidligere undersøgelse af digital kommunikation med det offentlige. Herudover er der tidligere gennemført en undersøgelse af e-mail svar og svartider i New Zealand og Australien. De danske resultater fra e-mail undersøgelsen...

  5. Diagnoseforsinkelser i almen praksis II: Dilemmaer i den diagnostiske proces

    DEFF Research Database (Denmark)

    Wentzer, Helle Sofie; Andersen, Rikke Sand; Bundgaard, Henning

    2016-01-01

    Sundhedspolitisk er der fokus på diagnoseforsinkelser. Det er der også i forskningen og i klinisk praksis. Artiklen er den anden af to, der ser på diagnoseforsinkelser og de overvejelser og dilemmaer, der indgår i den diagnostiske proces. Mens den første artikel fokuserede på forsinkelsesskabende....... Workshoppen tog afsæt i to patientcases med diagnoseforsinkelser med henblik på at ”trigge” deltagernes erfaringer med strukturelle problematikker i egen praksis. Resultatet er en beskrivelse af en række dilemmaer i den diagnostiske proces....

  6. Vidensledelse og den sociale dimension i deling af viden

    DEFF Research Database (Denmark)

    Lauring, Jakob

    2004-01-01

    gør vidensbegrebet interessant i forhold til ledelse af virksomheder. - Fokus på de sociale barrierer for deling af viden Jeg vil i det kommende illustrere, hvilke betydninger den sociale dimension i deling af viden kan have for videnledelse. Det vil jeg gøre gennem beskrivelser af to forskellige...... sociale barrierer for vidensdeling - den afgrænsende og den begrænsende. Der bliver ofte ikke taget hensyn til disse barrierer i systemer for videnledelse. I stedet antages det, at den sociale interaktion fungerer tilfredsstillende. Alligevel kan de have en meget stor betydning for vidensintensive...

  7. Konservatismen og den højreradikale terror

    DEFF Research Database (Denmark)

    2011-01-01

    Den norske højreekstremist Anders Behring Breiviks terror mod det norske samfund har herhjemme ledt til en voldsom debat om blandt andet forbindelsen mellem tonen i debatten og terrorangrebet og forholdet mellem den siden 2001 meget omtalte kulturkonservatisme og Anders Breiviks terrorhandling....... Essayet Konservatismen og den højreradikale terror forsøger dels at skabe klarhed over fronterne i debatten, dels at rette en kritik mod såvel tendensen til at afskrive handlingen som uforståelig som af tendensen til at slå den bredere højrefløjs kritik af multikulturalismen i hartkorn med Breiviks...

  8. Mozart, Karl Barth, og den kristne troslæren

    DEFF Research Database (Denmark)

    Petersen, Nils Holger

    2010-01-01

    En diskussion af Karl Barths teologiske brug af W.A.Mozart i den kirchliche Dogmatik med kontekstuel inddragelse af en til en vis grad tilsvarende overordnet diskussion af Mozart, skrevet af en samtidig musiker, den fremtrædende Mozart-dirigent Ferenc Fricsay. ......En diskussion af Karl Barths teologiske brug af W.A.Mozart i den kirchliche Dogmatik med kontekstuel inddragelse af en til en vis grad tilsvarende overordnet diskussion af Mozart, skrevet af en samtidig musiker, den fremtrædende Mozart-dirigent Ferenc Fricsay. ...

  9. Feeding strategies as revealed by the section moduli of the humerus bones in bipedal theropod dinosaurs

    Science.gov (United States)

    Lee, Scott; Richards, Zachary

    2015-03-01

    The section modulus of a bone is a measure of its ability to resist bending torques. Carnivorous dinosaurs presumably had strong arm bones to hold struggling prey during hunting. Some theropods are believed to have become herbivorous and such animals would not have needed such strong arms. In this work, the section moduli of the humerus bones of bipedal theropod dinosaurs (from Microvenator celer to Tyrannosaurus rex) are studied to determine the maximum bending loads their arms could withstand. The results show that bending strength is not of uniform importance to these magnificent animals. The predatory theropods had strong arms for use in hunting. In contrast, the herbivorous dinosaurs had weaker arms.

  10. Ichnological evidence of Megalosaurid Dinosaurs Crossing Middle Jurassic Tidal Flats.

    Science.gov (United States)

    Razzolini, Novella L; Oms, Oriol; Castanera, Diego; Vila, Bernat; Santos, Vanda Faria Dos; Galobart, Àngel

    2016-08-19

    A new dinosaur tracksite in the Vale de Meios quarry (Serra de Aire Formation, Bathonian, Portugal)preserves more than 700 theropod tracks. They are organized in at least 80 unidirectional trackways arranged in a bimodal orientation pattern (W/NW and E/SE). Quantitative and qualitative comparisons reveal that the large tridactyl, elongated and asymmetric tracks resemble the typical Late Jurassic-Early Cretaceous Megalosauripus ichnogenus in all morphometric parameters. Few of the numerous tracks are preserved as elite tracks while the rest are preserved as different gradients of modified true tracks according to water content, erosive factors, radial fractures and internal overtrack formations. Taphonomical determinations are consistent with paleoenvironmental observations that indicate an inter-tidal flat located at the margin of a coastal barrier. The Megalosauripus tracks represent the oldest occurrence of this ichnotaxon and are attributed to large megalosaurid dinosaurs. Their occurrence in Vale de Meios tidal flat represents the unique paleoethological evidence of megalosaurids moving towards the lagoon, most likley during the low tide periods with feeding purposes.

  11. Ichnological evidence of Megalosaurid Dinosaurs Crossing Middle Jurassic Tidal Flats

    Science.gov (United States)

    Razzolini, Novella L.; Oms, Oriol; Castanera, Diego; Vila, Bernat; Santos, Vanda Faria Dos; Galobart, Àngel

    2016-08-01

    A new dinosaur tracksite in the Vale de Meios quarry (Serra de Aire Formation, Bathonian, Portugal)preserves more than 700 theropod tracks. They are organized in at least 80 unidirectional trackways arranged in a bimodal orientation pattern (W/NW and E/SE). Quantitative and qualitative comparisons reveal that the large tridactyl, elongated and asymmetric tracks resemble the typical Late Jurassic-Early Cretaceous Megalosauripus ichnogenus in all morphometric parameters. Few of the numerous tracks are preserved as elite tracks while the rest are preserved as different gradients of modified true tracks according to water content, erosive factors, radial fractures and internal overtrack formations. Taphonomical determinations are consistent with paleoenvironmental observations that indicate an inter-tidal flat located at the margin of a coastal barrier. The Megalosauripus tracks represent the oldest occurrence of this ichnotaxon and are attributed to large megalosaurid dinosaurs. Their occurrence in Vale de Meios tidal flat represents the unique paleoethological evidence of megalosaurids moving towards the lagoon, most likley during the low tide periods with feeding purposes.

  12. 2004 assessment of habitat improvements in Dinosaur Reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Blackman, B.G.; Cowie, D.M.

    2005-01-15

    Formed in 1979 after the completion of the Peace Canyon Dam, Dinosaur Reservoir is 21 km long and backs water up to the tailrace of W.A.C. Bennett Dam. BC Hydro has funded studies to evaluate fish stocking programs and assess habitat limitations and potential enhancements as part of a water licence agreement. The Peace/Williston Fish and Wildlife Compensation Programs (PWFWCP) have undertaken a number of projects to address fish habitat limitations, entrainment and stocking assessments as a result of recommendations stemming from these studies. It was determined that existing baseline fish data was needed in order to evaluate the effectiveness of these activities. A preliminary boat electro-fishing program which was started in October 2001, noted that a propensity for rainbow trout to concentrate near woody debris. In response, a program was started in 2002 to add woody debris to embayment areas throughout the reservoir. These enhanced woody debris structures are located in small sheltered bays and consist of a series of large trees cabled together and anchored to the shore. The area between the cabled trees and the shoreline is filled with woody debris and root wads collected from along the shoreline. The 2004 assessment of habitat improvements in Dinosaur Reservoir presents the findings from a study that compares the number of fish captured using trap nets, angling, and minnow traps, at the woody debris structures to sites with similar physical characteristics where woody debris had not been added. 17 refs., 5 tabs., 4 figs.

  13. The first well-preserved coelophysoid theropod dinosaur from Asia.

    Science.gov (United States)

    You, Hai-Lu; Azuma, Yoichi; Wang, Tao; Wang, Ya-Ming; Dong, Zhi-Ming

    2014-10-16

    Coelophysoid dinosaurs represent the earliest major radiation of neotheropods. These small-to-medium-sized agile bipeds lived throughout much of Pangaea during the Late Triassic-arly Jurassic. Previously reported coelophysoid material from Asia (excluding the Gondwanan territory of India) is limited to two specimens that comprise only limb fragments. This paper describes a new genus and species of coelophysoid, Panguraptor lufengensis, from the Lower Jurassic Lufeng Formation of Yunnan Province, China. The new taxon is represented by a well-preserved skeleton, including the skull and lower jaw, the presacral vertebral column and partial ribs, the right scapula, a partial forelimb, part of the pelvic girdle, and an almost complete hind limb. It is distinguished from other coelophysoid theropods by the unique combination of the following three character states: 1) diagonal (rostrodorsal-caudoventral) ridge on lateral surface of maxilla, within antorbital fossa, 2) elliptical, laterally facing fenestra caudodorsal to aforementioned diagonal ridge, and 3) hooked craniomedial corner of distal tarsal IV. Cladistic analysis recovers Panguraptor lufengensis deeply nested within Coelophysoidea as a member of Coelophysidae, and it is more closely related to Coelophysis than to "Syntarsus". Panguraptor represents the first well-preserved coelophysoid theropod dinosaur from Asia, and provides fresh evidence supporting the hypothesis that terrestrial tetrapods tended to be distributed pan-continentally during the Early Jurassic.

  14. Secondary cartilage revealed in a non-avian dinosaur embryo.

    Directory of Open Access Journals (Sweden)

    Alida M Bailleul

    Full Text Available The skull and jaws of extant birds possess secondary cartilage, a tissue that arises after bone formation during embryonic development at articulations, ligamentous and muscular insertions. Using histological analysis, we discovered secondary cartilage in a non-avian dinosaur embryo, Hypacrosaurus stebingeri (Ornithischia, Lambeosaurinae. This finding extends our previous report of secondary cartilage in post-hatching specimens of the same dinosaur species. It provides the first information on the ontogeny of avian and dinosaurian secondary cartilages, and further stresses their developmental similarities. Secondary cartilage was found in an embryonic dentary within a tooth socket where it is hypothesized to have arisen due to mechanical stresses generated during tooth formation. Two patterns were discerned: secondary cartilage is more restricted in location in this Hypacrosaurus embryo, than it is in Hypacrosaurus post-hatchlings; secondary cartilage occurs at far more sites in bird embryos and nestlings than in Hypacrosaurus. This suggests an increase in the number of sites of secondary cartilage during the evolution of birds. We hypothesize that secondary cartilage provided advantages in the fine manipulation of food and was selected over other types of tissues/articulations during the evolution of the highly specialized avian beak from the jaws of their dinosaurian ancestors.

  15. Histological evidence for a supraspinous ligament in sauropod dinosaurs

    Science.gov (United States)

    Cerda, Ignacio A.; Casal, Gabriel A.; Martinez, Rubén D.; Ibiricu, Lucio M.

    2015-01-01

    Supraspinous ossified rods have been reported in the sacra of some derived sauropod dinosaurs. Although different hypotheses have been proposed to explain the origin of this structure, histological evidence has never been provided to support or reject any of them. In order to establish its origin, we analyse and characterize the microstructure of the supraspinous rod of two sauropod dinosaurs from the Upper Cretaceous of Argentina. The supraspinous ossified rod is almost entirely formed by dense Haversian bone. Remains of primary bone consist entirely of an avascular tissue composed of two types of fibre-like structures, which are coarse and longitudinally (parallel to the main axis of the element) oriented. These structures are differentiated on the basis of their optical properties under polarized light. Very thin fibrous strands are also observed in some regions. These small fibres are all oriented parallel to one another but perpendicular to the element main axis. Histological features of the primary bone tissue indicate that the sacral supraspinous rod corresponds to an ossified supraspinous ligament. The formation of this structure appears to have been a non-pathological metaplastic ossification, possibly induced by the continuous tensile forces applied to the element. PMID:26587248

  16. Biology of the sauropod dinosaurs: the evolution of gigantism.

    Science.gov (United States)

    Sander, P Martin; Christian, Andreas; Clauss, Marcus; Fechner, Regina; Gee, Carole T; Griebeler, Eva-Maria; Gunga, Hanns-Christian; Hummel, Jürgen; Mallison, Heinrich; Perry, Steven F; Preuschoft, Holger; Rauhut, Oliver W M; Remes, Kristian; Tütken, Thomas; Wings, Oliver; Witzel, Ulrich

    2011-02-01

    The herbivorous sauropod dinosaurs of the Jurassic and Cretaceous periods were the largest terrestrial animals ever, surpassing the largest herbivorous mammals by an order of magnitude in body mass. Several evolutionary lineages among Sauropoda produced giants with body masses in excess of 50 metric tonnes by conservative estimates. With body mass increase driven by the selective advantages of large body size, animal lineages will increase in body size until they reach the limit determined by the interplay of bauplan, biology, and resource availability. There is no evidence, however, that resource availability and global physicochemical parameters were different enough in the Mesozoic to have led to sauropod gigantism. We review the biology of sauropod dinosaurs in detail and posit that sauropod gigantism was made possible by a specific combination of plesiomorphic characters (phylogenetic heritage) and evolutionary innovations at different levels which triggered a remarkable evolutionary cascade. Of these key innovations, the most important probably was the very long neck, the most conspicuous feature of the sauropod bauplan. Compared to other herbivores, the long neck allowed more efficient food uptake than in other large herbivores by covering a much larger feeding envelope and making food accessible that was out of the reach of other herbivores. Sauropods thus must have been able to take up more energy from their environment than other herbivores. The long neck, in turn, could only evolve because of the small head and the extensive pneumatization of the sauropod axial skeleton, lightening the neck. The small head was possible because food was ingested without mastication. Both mastication and a gastric mill would have limited food uptake rate. Scaling relationships between gastrointestinal tract size and basal metabolic rate (BMR) suggest that sauropods compensated for the lack of particle reduction with long retention times, even at high uptake rates. The

  17. Biology of the sauropod dinosaurs: the evolution of gigantism

    Science.gov (United States)

    Sander, P Martin; Christian, Andreas; Clauss, Marcus; Fechner, Regina; Gee, Carole T; Griebeler, Eva-Maria; Gunga, Hanns-Christian; Hummel, Jürgen; Mallison, Heinrich; Perry, Steven F; Preuschoft, Holger; Rauhut, Oliver W M; Remes, Kristian; Tütken, Thomas; Wings, Oliver; Witzel, Ulrich

    2011-01-01

    The herbivorous sauropod dinosaurs of the Jurassic and Cretaceous periods were the largest terrestrial animals ever, surpassing the largest herbivorous mammals by an order of magnitude in body mass. Several evolutionary lineages among Sauropoda produced giants with body masses in excess of 50 metric tonnes by conservative estimates. With body mass increase driven by the selective advantages of large body size, animal lineages will increase in body size until they reach the limit determined by the interplay of bauplan, biology, and resource availability. There is no evidence, however, that resource availability and global physicochemical parameters were different enough in the Mesozoic to have led to sauropod gigantism. We review the biology of sauropod dinosaurs in detail and posit that sauropod gigantism was made possible by a specific combination of plesiomorphic characters (phylogenetic heritage) and evolutionary innovations at different levels which triggered a remarkable evolutionary cascade. Of these key innovations, the most important probably was the very long neck, the most conspicuous feature of the sauropod bauplan. Compared to other herbivores, the long neck allowed more efficient food uptake than in other large herbivores by covering a much larger feeding envelope and making food accessible that was out of the reach of other herbivores. Sauropods thus must have been able to take up more energy from their environment than other herbivores. The long neck, in turn, could only evolve because of the small head and the extensive pneumatization of the sauropod axial skeleton, lightening the neck. The small head was possible because food was ingested without mastication. Both mastication and a gastric mill would have limited food uptake rate. Scaling relationships between gastrointestinal tract size and basal metabolic rate (BMR) suggest that sauropods compensated for the lack of particle reduction with long retention times, even at high uptake rates. The

  18. 1994 prairie dog burrow mapping with Global Positioning Systems, UL Bend National Wildlife Refuge, Phillips County, Montana

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Holes in the ground are a very important feature of black-footed ferret habitat. The number, distribution, and activity level of prairie dog burrows is related to...

  19. Burrowing nematodes from Colombia and their relationship with Radopholus similis populations,R. arabocoffeae and R. duriophilus

    NARCIS (Netherlands)

    Múnera Uribe, G.E.; Bert, W.; Vierstraete, A.R.; Peña, de la E.; Moens, M.; Decraemer, W.

    2010-01-01

    Two burrowing nematode populations from Colombia were characterised using morphological, morphometric and molecular criteria. The morphological and morphometric characters of the two populations did not differ from those of Radopholus similis. The phylogenetic analysis based on sequence comparison o

  20. First field record of mangrove crab Ucides cordatus (Crustacea: Decapoda: Ucididae recruits co-inhabiting burrows of conspecific crabs

    Directory of Open Access Journals (Sweden)

    Anders Jensen Schmidt

    2009-12-01

    Full Text Available Recruits of the mangrove crab Ucides cordatus (Linnaeus, 1763, rarely encountered in the field were found co-inhabiting burrows of larger male and female conspecifics in the mangrove forest. They were located in the sediment of the inner walls and burrow plugs. Average carapace width (CW of the hosting and co-inhabiting crabs was 3.8 ± 0.20 and 0.9 ± 0.03, respectively. As shown by the size-frequency distribution, while most recruits leave the conspecific burrows after reaching 1.0 cm CW, some stay until they reach a size of 2.5 cm CW. The results of this study contribute to a better understanding of recruitment patterns in this ecologically and economically important mangrove crab species. Follow-up studies are however needed to fully determine the role of conspecific burrows for juvenile habitat choice and survivorship in U. cordatus.

  1. Den digitale pædagoguddannelse

    DEFF Research Database (Denmark)

    Pilgaard, Michal; Rasmussen, Jan Erik Røjkjær; Ahm, Jacob Noer

    2016-01-01

    Udviklingsprojektet ”Den digitale pædagoguddannelse” er en samlebetegnelse for en række delprojekter, der alle er udført på tværs af udbudsstederne af pædagoguddannelsen i VIA i 2015. Fælles for projekterne er, at de indeholder konkrete erfaringer med at inddrage digitale medier i...... pædagoguddannelsen, og at de udspringer af en eksperimenterende udforskning af følgende grundlæggende spørgsmål: "Hvordan integrerer vi de digitale medier på en meningsfuld måde i didaktikken på pædagoguddannelsen?" Dertil beskæftiger enkelte af projekterne sig med spørgsmålet om, hvordan vi kvalificerer vores...

  2. Black-footed ferrets and recreational shooting influence the attributes of black-tailed prairie dog burrows

    Science.gov (United States)

    Biggins, Dean E.; Ramakrishnan, Shantini; Goldberg, Amanda R.; Eads, David A.

    2012-01-01

    Black-tailed prairie dogs (Cynomys ludovicianus) plug burrows occupied by black-footed ferrets (Mustela nigripes), and they also plug burrows to entomb dead prairie dogs. We further evaluated these phenomena by sampling connectivity and plugging of burrow openings on prairie dog colonies occupied by ferrets, colonies where recreational shooting was allowed, and colonies with neither shooting nor ferrets. We counted burrow openings on line surveys and within plots, classified surface plugging, and used an air blower to examine subsurface connectivity. Colonies with ferrets had lower densities of openings, fewer connected openings (suggesting increased subsurface plugging), and more surface plugs compared to colonies with no known ferrets. Colonies with recreational shooting had the lowest densities of burrow openings, and line-survey data suggested colonies with shooting had intermediate rates of surface plugging. The extent of surface and subsurface plugging could have consequences for the prairie dog community by changing air circulation and escape routes of burrow systems and by altering energetic relationships. Burrow plugging might reduce prairie dogs' risk of predation by ferrets while increasing risk of predation by American badgers (Taxidea taxus); however, the complexity of the trade-off is increased if plugging increases the risk of predation on ferrets by badgers. Prairie dogs expend more energy plugging and digging when ferrets or shooting are present, and ferrets increase their energy expenditures when they dig to remove those plugs. Microclimatic differences in plugged burrow systems may play a role in flea ecology and persistence of the flea-borne bacterium that causes plague (Yersinia pestis).

  3. Map-Based Repowering and Reorganization of a Wind Resource Area to Minimize Burrowing Owl and Other Bird Fatalities

    OpenAIRE

    Lee Neher; K. Shawn Smallwood; Bell, Douglas A.

    2009-01-01

    Wind turbines in the Altamont Pass Wind Resource Area (Alameda/Contra Costa Counties, California, USA) generate about 730 GWh of electricity annually, but have been killing thousands of birds each year, including >2,000 raptors and hundreds of burrowing owls. We have developed collision hazard maps and hazard ratings of wind turbines to guide relocation of existing wind turbines and careful repowering to modern turbines to reduce burrowing owl fatalities principally, and other birds second...

  4. Standardized Monitoring Strategies for Burrowing Owls on DoD Installations

    Science.gov (United States)

    2006-12-01

    whether each owl was detected visually, vocally , or both. Each adult owl detected at a survey point gets its own line, juveniles associated with one...measurements (tail length, meta-tarsus, wing chord ) are made on adult birds that allow comparison of body size between sexes and sites. Age...Burrowing Owls will have a brood patch. Adult Left Wing 180 Use the method shown in Appendix II to measure the owl’s left wing chord length. Record

  5. Long-term population dynamics of a managed burrowing owl colony

    Science.gov (United States)

    Barclay, John H.; Korfanta, Nicole M.; Kauffman, Matthew J.

    2011-01-01

    We analyzed the population dynamics of a burrowing owl (Athene cunicularia) colony at Mineta San Jose International Airport in San Jose, California, USA from 1990-2007. This colony was managed by using artificial burrows to reduce the occurrence of nesting owls along runways and within major airport improvement projects during the study period. We estimated annual reproduction in natural and artificial burrows and age-specific survival rates with mark-recapture techniques, and we estimated the relative contribution of these vital rates to population dynamics using a life table response experiment. The breeding colony showed 2 distinct periods of change: high population growth from 7 nesting pairs in 1991 to 40 pairs in 2002 and population decline to 17 pairs in 2007. Reproduction was highly variable: annual nesting success (pairs that raised =1 young) averaged 79% and ranged from 36% to 100%, whereas fecundity averaged 3.36 juveniles/pair and ranged from 1.43 juveniles/pair to 4.54 juveniles/pair. We estimated annual adult survival at 0.710 during the period of colony increase from 1996 to 2001 and 0.465 during decline from 2002 to 2007, but there was no change in annual survival of juveniles between the 2 time periods. Long-term population growth rate (lambda) estimated from average vital rates was lambdaa=1.072 with lambdai=1.288 during colony increase and lambdad=0.921 (DELTA lambda=0.368) during decline. A life table response experiment showed that change in adult survival rate during increasing and declining phases explained more than twice the variation in growth rate than other vital rates. Our findings suggest that management and conservation of declining burrowing owl populations should address factors that influence adult survival.

  6. Razor clam to RoboClam: burrowing drag reduction mechanisms and their robotic adaptation.

    Science.gov (United States)

    Winter, A G; V; Deits, R L H; Dorsch, D S; Slocum, A H; Hosoi, A E

    2014-09-01

    Estimates based on the strength, size, and shape of the Atlantic razor clam (Ensis directus) indicate that the animal's burrow depth should be physically limited to a few centimeters; yet razor clams can dig as deep as 70 cm. By measuring soil deformations around burrowing E. directus, we have found the animal reduces drag by contracting its valves to initially fail, and then fluidize, the surrounding substrate. The characteristic contraction time to achieve fluidization can be calculated directly from soil properties. The geometry of the fluidized zone is dictated by two commonly-measured geotechnical parameters: coefficient of lateral earth pressure and friction angle. Calculations using full ranges for both parameters indicate that the fluidized zone is a local effect, occurring between 1-5 body radii away from the animal. The energy associated with motion through fluidized substrate-characterized by a depth-independent density and viscosity-scales linearly with depth. In contrast, moving through static soil requires energy that scales with depth squared. For E. directus, this translates to a 10X reduction in the energy required to reach observed burrow depths. For engineers, localized fluidization offers a mechanically simple and purely kinematic method to dramatically reduce energy costs associated with digging. This concept is demonstrated with RoboClam, an E. directus-inspired robot. Using a genetic algorithm to find optimal digging kinematics, RoboClam has achieved localized fluidization burrowing performance comparable to that of the animal, with a linear energy-depth relationship, in both idealized granular glass beads and E. directus' native cohesive mudflat habitat.

  7. Trophic eggs compensate for poor offspring feeding capacity in a subsocial burrower bug

    OpenAIRE

    Baba, Narumi; Hironaka, Mantaro; Hosokawa, Takahiro; Mukai, Hiromi; Nomakuchi, Shintaro; Ueno, Takatoshi

    2010-01-01

    Various animals produce inviable eggs or egg-like structures called trophic eggs, which are presumed to be an extended maternal investment for the offspring. However, there is little knowledge about the ecological or physiological constraints associated with their evolutionary origin. Trophic eggs of the seminivorous subsocial burrower bug (Canthophorus niveimarginatus) have some unique characteristics. Trophic eggs are obligate for nymphal survival, and first-instar nymphs die without them. ...

  8. Prospecting for dinosaurs on the mining frontier: The value of information in America's Gilded Age.

    Science.gov (United States)

    Rieppel, Lukas

    2015-04-01

    How much is a dinosaur worth? This essay offers an account of the way vertebrate fossils were priced in late 19th-century America to explore the process by which monetary values are established in science. Examining a long and drawn-out negotiation over the sale of an unusually rich dinosaur quarry in Wyoming, I argue that, on their own, abstract market principles did not suffice to mediate between supply and demand. Rather, people haggling over the price of dinosaur bones looked to social norms from the mineral industry for cues on how to value these rare and unusual objects, adopting a set of negotiation tactics that exploited asymmetries in the distribution of scarce information to secure the better end of the deal. On the mining frontier in America's Gilded Age, dinosaurs were thus valued in much the same way as any other scarce natural resource one could dig out of the ground, including gold, silver, and coal.

  9. Den alimentære kode - Centralbrasilien, Israel, Helvede

    DEFF Research Database (Denmark)

    Jensen, Hans Jørgen Lundager

    2006-01-01

    Den alimentære kode som centralt antropologisk emne hos Claude Lévi-Strauss og i gammeltestamentlig og senere kristen mytologi......Den alimentære kode som centralt antropologisk emne hos Claude Lévi-Strauss og i gammeltestamentlig og senere kristen mytologi...

  10. Den Ontologiske Vending i Antropologi og Science and Technology Studies

    DEFF Research Database (Denmark)

    Winthereik, Brit Ross

    2015-01-01

    Formålet med artiklen er at afsøge, hvad videnskabs- og teknologi- studier eller Science and Technology Studies (STS) tilbyder humaniora og samfundsvidenskaberne med det nybrud, der er blevet kaldt den ontologiske vending. Med udgangspunkt i en beskrivelse af den onto- logiske vending i antropologi...

  11. Laika – den første hund i rummet

    DEFF Research Database (Denmark)

    Alstrup, Aage Kristian Olsen

    2013-01-01

    DETTE ER DEN FØRSTE ARTIKEL I EN SERIE OM FORSØGSDYRENES ROLLE I RUMFORSKNINGEN. DYRENE SPILLEDE EN CENTRAL ROLLE I RUSSERNES OG AMERIKANERNES RUMKAPLØB UNDER DEN KOLDE KRIG. I DAG BRUGES DYRENE TIL MEDICINSKE FORSØG UDFØRT I VÆGTLØS TILSTAND. FØRSTE ARTIKEL HANDLER OM GADEKRYDSET LAIKA, SOM BLEV...

  12. Empirisme, rationalisme og den moralske følelse

    DEFF Research Database (Denmark)

    Nielsen, Carsten Fogh

    2003-01-01

    Sammenlignende diskussion af David Humes og Immanuel Kants syn på følelsernes rolle for den moralske dom......Sammenlignende diskussion af David Humes og Immanuel Kants syn på følelsernes rolle for den moralske dom...

  13. Tegnets tid. Fortid, historie og historicitet efter den sproglige vending

    DEFF Research Database (Denmark)

    Simonsen, Dorthe Gert

    historieskrivningens sandhedsfordring. Her ud fra forskydes det snævre fokus på tegn, tekst og diskurs i den aktuelle historieteoretiske debat til spørgsmål om tid og “radikal historicitet”. Der indhentes eksempler fra nyere kulturhistorisk forskning, især fra den amerikanske New Historicism....

  14. Mephisto vor den Richtern – Mephisto before the judges

    Directory of Open Access Journals (Sweden)

    Czarnikow Marie

    2014-08-01

    Full Text Available Mephisto before the judges: The Mephisto trials – how the reader was discovered, and then denied any decision‐making capacity Mephisto vor den Richtern – Von der Entdeckung zur Entmündigung des Lesers in den Mephisto‐Prozessen

  15. Samarbejdets betydning i den ’klassiske udlicitering’

    DEFF Research Database (Denmark)

    Lindholst, Andrej Christian

    2015-01-01

    Hvilken betydning har ’samarbejde’ i kontraktstyringen mellem offentlige myndigheder og private entreprenører inden for de ’klassiske’ udbudsområder? I både den administrative praksis og den politologiske litteratur betragtes en effektiv anvendelse af udlicitering på de klassiske udbudsområder of...

  16. Anaïs Nin, pornografien og den kvinnelige seksualiteten

    OpenAIRE

    Tronvold, Gry Olsen

    2010-01-01

    Denne studien tar for seg Anaïs Nins samlinger Delta of venus (1977) og Little Birds (1979) I lys av Sigmund Freud argumenterer jeg for at Nins pornografi er metapornografi, som belyser problematiske aspekter ved den kvinnelige seksualiteten. Slik finner jeg belegg for at Nins samlinger er skjønnlitterære og dermed bryter med den konvensjonelle pornografien.

  17. Margaret Thatcher og afslutningen på Den Kolde Krig

    DEFF Research Database (Denmark)

    Sevaldsen, Jørgen

    2010-01-01

    Gennemgang af den britiske premierminister (1979-1990) Margaret Thatchers rolle i forbindelse med Murens fald i 1989. Med dansk perspektiv.......Gennemgang af den britiske premierminister (1979-1990) Margaret Thatchers rolle i forbindelse med Murens fald i 1989. Med dansk perspektiv....

  18. Synteserapport & 1. Indenrigspolitiske forhold i Den Islamiske Republik Iran

    DEFF Research Database (Denmark)

    Pedersen, Claus Valling

    Rapport til Udenrigsministeriet om de indenrigspolitiske forhold i Iran samt et syntese af hele rapporten: Iran som regional og international medspiller i den globale verdensorden samt Irans indenrigspolitik......Rapport til Udenrigsministeriet om de indenrigspolitiske forhold i Iran samt et syntese af hele rapporten: Iran som regional og international medspiller i den globale verdensorden samt Irans indenrigspolitik...

  19. Burrowing, byssus, and biomarkers: behavioral and physiological indicators of sublethal thermal stress in freshwater mussels (Unionidae)

    Science.gov (United States)

    Archambault, Jennifer M.; Cope, W. Gregory; Kwak, Thomas J.

    2013-01-01

    Recent research has elucidated the acute lethal effects of elevated water temperatures to glochidia (larvae), juvenile, and adult life stages of freshwater mussels (Order Unionida), but few studies have focused on sublethal effects of thermal stress. We evaluated the sublethal effects of elevated temperature on burrowing behavior and byssus production in juveniles, and on enzymatic biomarkers of stress in adults in acute (96 h) laboratory experiments in sediment, with two acclimation temperatures (22 and 27 °C) and two experimental water levels (watered and dewatered) as proxies for flow regime. Increasing temperature significantly reduced burrowing in all five species tested, and the dewatered treatment (a proxy for drought conditions) reduced burrowing in all but Amblema plicata. Production of byssal threads was affected most drastically by flow regime, with the probability of byssus presence reduced by 93–99% in the dewatered treatment, compared to the watered treatment (a proxy for low flow conditions); increasing temperature alone reduced byssus by 18–35%. Alanine aminotransferase and aspartate aminotransferase were significantly affected by treatment temperature in the 27 °C acclimation, watered test (p = 0.04 and 0.02, respectively). Our results are important in the context of climate change, because stream temperature and flow are expected to change with increasing air temperature and altered precipitation patterns.

  20. Effects of invasive rats and burrowing seabirds on seeds and seedlings on New Zealand islands.

    Science.gov (United States)

    Grant-Hoffman, Madeline N; Mulder, Christa P H; Bellingham, Peter J

    2010-04-01

    Rats (Rattus rattus, Rattus norvegicus, Rattus exulans) are important invaders on islands. They alter vegetation indirectly by preying on burrowing seabirds. These seabirds affect vegetation through nutrient inputs from sea to land and physical disturbance through trampling and burrowing. Rats also directly affect vegetation though consumption of seeds and seedlings. Seedling communities on northern New Zealand islands differ in composition and densities among islands which have never been invaded by rats, are currently invaded by rats, or from which rats have been eradicated. We conducted experimental investigations to determine the mechanisms driving these patterns. When the physical disturbance of seabirds was removed, in soils collected from islands and inside exclosures, seedling densities increased with seabird burrow density. For example, seedling densities inside exclosures were 10 times greater than those outside. Thus the negative effects of seabirds on seedlings, by trampling and uprooting, overwhelm the potentially beneficial effects of high levels of seed germination, seedling emergence, and possibly seed production, which result from seed burial and nutrient additions. Potential seedling density was reduced on an island where rats were present, germination of seeds from soils of this island was approximately half that found on other islands, but on this island seedling density inside exclosures was 7 times the density outside. Although the total negative effects of seabirds and rats on seedling densities are similar (reduced seedling density), the differences in mechanisms and life stages affected result in very different filters on the plant community.

  1. Distribution of the Chuckwalla, Western Burrowing Owl, and Six Bat Species on the Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    Cathy A. Willis

    1997-05-01

    Field Surveys were conducted in 1996 to determine the current distribution of several animal species of concern on the Nevada Test Site (NTS). They included the chuckwall (Sauromalus obesus), western burrowing owl (Speotyto cunicularia), and six species of bats. Nineteen chuckwallas and 118 scat locations were found during the chuckwalla field study. Eighteen western burrowing owls were found at 12 sighting locations during the 1996 field study. Of the eleven bat species of concern which might occur on the NTS, five, and possibly six, were captured during this survey. The U.S. Department of Energy, Nevada Operations Office, takes certain management actions to protect and conserve the chuckwalla, western burrowing owl, and bats on the NTS. These actions are described and include: (1) conducting surveys at sites of proposed land-disturbing activities (2) altering projects whenever possible to avoid or minimize impacts to these species (3) maintaining a geospatial database of known habitat for species of concern (4) sharing sighting and trap location data gathered on the NTS with other local land and resource managers, and (5) conducting periodic field surveys to monitor these species distribution and relative abundance on the NTS.

  2. Bioassessment of contaminant transport and distribution in aquatic ecosystems by chemical analysis of burrowing mayflies (Hexagenia)

    Science.gov (United States)

    Steingraeber, M.T.; Wiener, J.G.

    1995-01-01

    Burrowing mayfly nymphs (Ephemeroptera) inhabit and ingest fine-grained sediments and detritus that may be enriched with metals and persistent organic compounds. The burrowing nymphs can externally adsorb and internally assimilate these contaminants, providing a link for the food chain transfer of potentially toxic substances from sediments to organisms in higher trophic levels. The emergent adults are short-lived and do not feed, thus their gut contents do not contribute greatly to their total contaminant burden. These characteristics make Hexagenia spp. And certain other burrowing mayflies useful for assessing ecosystem contamination. General protocols are presented for the collection, processing and analysis of emergent mayflies to assess the spatial distribution and bioaccumulation of sediment-associated contaminants in aquatic ecosystems. Two essential components of this bioassessment approach are a network of on-site volunteers with the materials and instructions needed to correctly collect and store samples and quality assurance procedures to estimate the accuracy of chemical analyses. The utility of this approach is demonstrated with an example of its application to the Upper Mississippi River (USA). Determination of cadmium, mercury and polychlorinated biphenyl congeners in emergent Hexagenia bilineata from a 1250 km reach of this river revealed (1) several source areas of contaminants and (2) distinct patterns in the bioaccumulation (and apparent sediment-associated transport) of each residue on both small and large spatial scales.

  3. Dinosaur footprints in the Upper Turonian-Coniacian limestone in the Krnica Bay (NE Istria, Croatia

    Directory of Open Access Journals (Sweden)

    Alenka Mauko

    2003-06-01

    Full Text Available Three isolated footprints and one trackway that can be attributed to bipedal dinosaur, from a limestone bed in vicinity of Požara promontory, Krnica Bay, are described. According to the stratigraphic position the footprints are late Turonian to Coniacian in age.This is the first record of dinosaur remains in the Turonian-Coniacian and the youngest footprint site on the Adriatic-Dinaric Carbonate Platform described thus far.

  4. Dental histology of Coelophysis bauri and the evolution of tooth attachment tissues in early dinosaurs.

    Science.gov (United States)

    Fong, Raymond K M; LeBlanc, Aaron R H; Berman, David S; Reisz, Robert R

    2016-07-01

    Studies of dinosaur teeth have focused primarily on external crown morphology and thus, use shed or in situ tooth crowns, and are limited to the enamel and dentine dental tissues. As a result, the full suites of periodontal tissues that attach teeth to the jaws remain poorly documented, particularly in early dinosaurs. These tissues are an integral part of the tooth and thus essential to a more complete understanding of dental anatomy, development, and evolution in dinosaurs. To identify the tooth attachment tissues in early dinosaurs, histological thin sections were prepared from the maxilla and dentary of a partial skull of the early theropod Coelophysis bauri from the Upper Triassic (Rhaetian- 209-201 Ma) Whitaker Quarry, New Mexico, USA. As one of the phylogenetically and geologically oldest dinosaurs, it is an ideal candidate for examining dental tissues near the base of the dinosaurian clade. The teeth of C. bauri exhibited a fibrous tooth attachment in which the teeth possessed five tissues: enamel, dentine, cementum, periodontal ligament (PDL), and alveolar bone. Our findings, coupled with those of more recent studies of ornithischian teeth, indicate that a tripartite periodontium, similar to that of crocodilians and mammals, is the plesiomorphic condition for dinosaurs. The occurrence of a tripartite periodontium in dinosaurs adds to the growing consensus that the presence of these tissues is the plesiomorphic condition for the major amniote clades. Furthermore, this study establishes the relative timing of tissue development and growth directions of periodontal tissues and provides the first comparative framework for future studies of dinosaur periodontal development, tooth replacement, and histology. J. Morphol. 277:916-924, 2016. © 2016 Wiley Periodicals, Inc.

  5. The furculae of the dromaeosaurid dinosaur Dakotaraptor steini are trionychid turtle entoplastra

    Directory of Open Access Journals (Sweden)

    Victoria M. Arbour

    2016-02-01

    Full Text Available Dakotaraptor steini is a recently described dromaeosaurid dinosaur from the Upper Cretaceous (Maastrichtian Hell Creek Formation of South Dakota. Included within the D. steini hypodigm are three elements originally identified as furculae, one of which was made part of the holotype specimen. We show that the elements described as D. steini ‘furculae’ are not theropod dinosaur furculae, but are rather trionychid turtle entoplastra referable to cf. Axestemys splendida. The hypodigm of D. steini should be adjusted accordingly.

  6. Wear biomechanics in the slicing dentition of the giant horned dinosaur Triceratops

    OpenAIRE

    Erickson, Gregory M.; Sidebottom, Mark A.; Kay, David I.; Turner, Kevin T.; Ip, Nathan; Norell, Mark A.; Sawyer, W. Gregory; Krick, Brandon A.

    2015-01-01

    Herbivorous reptiles rarely evolve occluding dentitions that allow for the mastication (chewing) of plant matter. Conversely, most herbivorous mammals have occluding teeth with complex tissue architectures that self-wear to complex morphologies for orally processing plants. Dinosaurs stand out among reptiles in that several lineages acquired the capacity to masticate. In particular, the horned ceratopsian dinosaurs, among the most successful Late Cretaceous dinosaurian lineages, evolved slici...

  7. Cretaceous anuran and dinosaur footprints from the Patuxent Formation of Virginia

    Science.gov (United States)

    Weems, R.E.; Bachman, J.M.

    1997-01-01

    Footprints of an anuran (gen. et sp. indet.), a theropod dinosaur (Megalosauropus sp.), and an ornithopod dinosaur (Amblydactylus sp.) have been recovered from the Lower Cretaceous Patuxent Formation in Stafford County, Virginia. These footprints are the first record of terrestrial vertebrates from Cretaceous strata in Virginia, and their discovery suggests that the scarcity of bones and teeth in the Patuxent probably is an artifact of preservation. The anuran trackway provides the oldest known direct evidence for hopping locomotion among these amphibians.

  8. Embryology of Early Jurassic dinosaur from China with evidence of preserved organic remains.

    Science.gov (United States)

    Reisz, Robert R; Huang, Timothy D; Roberts, Eric M; Peng, ShinRung; Sullivan, Corwin; Stein, Koen; LeBlanc, Aaron R H; Shieh, DarBin; Chang, RongSeng; Chiang, ChengCheng; Yang, Chuanwei; Zhong, Shiming

    2013-04-11

    Fossil dinosaur embryos are surprisingly rare, being almost entirely restricted to Upper Cretaceous strata that record the late stages of non-avian dinosaur evolution. Notable exceptions are the oldest known embryos from the Early Jurassic South African sauropodomorph Massospondylus and Late Jurassic embryos of a theropod from Portugal. The fact that dinosaur embryos are rare and typically enclosed in eggshells limits their availability for tissue and cellular level investigations of development. Consequently, little is known about growth patterns in dinosaur embryos, even though post-hatching ontogeny has been studied in several taxa. Here we report the discovery of an embryonic dinosaur bone bed from the Lower Jurassic of China, the oldest such occurrence in the fossil record. The embryos are similar in geological age to those of Massospondylus and are also assignable to a sauropodomorph dinosaur, probably Lufengosaurus. The preservation of numerous disarticulated skeletal elements and eggshells in this monotaxic bone bed, representing different stages of incubation and therefore derived from different nests, provides opportunities for new investigations of dinosaur embryology in a clade noted for gigantism. For example, comparisons among embryonic femora of different sizes and developmental stages reveal a consistently rapid rate of growth throughout development, possibly indicating that short incubation times were characteristic of sauropodomorphs. In addition, asymmetric radial growth of the femoral shaft and rapid expansion of the fourth trochanter suggest that embryonic muscle activation played an important role in the pre-hatching ontogeny of these dinosaurs. This discovery also provides the oldest evidence of in situ preservation of complex organic remains in a terrestrial vertebrate.

  9. Anmeldelse af Claus Friisberg: Ideen om et frit Danmark. Den nationalliberale bevægelses ideologi og politik - især i den formative periode (Varde 2003)

    DEFF Research Database (Denmark)

    Busck, Steen

    2003-01-01

    Anmeldelse af Claus Friisberg: Ideen om et frit Danmark. Den nationalliberale bevægelses ideologi og politik - især i den formative periode (Varde 2003)......Anmeldelse af Claus Friisberg: Ideen om et frit Danmark. Den nationalliberale bevægelses ideologi og politik - især i den formative periode (Varde 2003)...

  10. Mapping Metal Elements of Shuangbai Dinosaur Fossil by Synchrotron X-ray Fluorescence Microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y.; Qun, Y; Ablett, J

    2008-01-01

    The metal elements mapping of Shuangbai dinosaur fossil, was obtained by synchrotron x-ray fluorescence (SXRF). Eight elements, Ca, Mn, Fe, Cu, Zn, As, Y and Sr were determined. Elements As and Y were detected for the first time in the dinosaur fossil. The data indicated that metal elements are asymmetrical on fossil section. This is different from common minerals. Mapping metals showed that metal element As is few. The dinosaur most likely belongs to natural death. This is different from Zigong dinosaurs which were found dead from poisoning. This method has been used to find that metals Fe and Mn are accrete, and the same is true for Sr and Y. This study indicated that colloid granule Fe and Mn, as well as Sr and Y had opposite electric charges in lithification process of fossils. By this analysis, compound forms can be ascertained. Synchrotron light source x-ray fluorescence is a complementary method that shows mapping of metal elements at the dinosaur fossil, and is rapid, exact and intuitionist. This study shows that dinosaur fossil mineral imaging has a potential in reconstructing the paleoenvironment and ancient geology.

  11. Kosmetisk kirurgi og den transformérbare krop -en analyse af den amerikanske tv-serie Nip/Tuck

    DEFF Research Database (Denmark)

    Jerslev, Anne

    2009-01-01

    En analyse af krops- og kønsiscenesættelser i den amerikanske tv-serie om kosmetisk kirurgi Nip/Tuck......En analyse af krops- og kønsiscenesættelser i den amerikanske tv-serie om kosmetisk kirurgi Nip/Tuck...

  12. Review: Grigoleit, Grit: Integrationsvarianten. Die Hmong in den USA (2008 Buchbesprechung: Grigoleit, Grit: Integrationsvarianten. Die Hmong in den USA (2008

    Directory of Open Access Journals (Sweden)

    Hans-Bernd Zöllner

    2009-07-01

    Full Text Available Review of the monograph: Grigoleit, Grit (2008, Integrationsvarianten. Die Hmong in den USA, Passau: Verlag Karl Stutz, ISBN 978-3-88849-183-2, 250 pages Besprechung der Monographie: Grigoleit, Grit (2008, Integrationsvarianten. Die Hmong in den USA, Passau: Verlag Karl Stutz, ISBN 978-3-88849-183-2, 250 Seiten

  13. Middle Cretaceous dinosaur assemblages from northern Brazil and northern Africa and their implications for northern Gondwanan composition

    Science.gov (United States)

    Candeiro, Carlos Roberto A.

    2015-08-01

    Dinosaurs are one of the most dominant groups in Cretaceous reptilian faunas. A summary of their record in northern Brazil and northern Africa during the middle of the Cretaceous Period (Aptian-Cenomanian) is presented here. Dinosaurs are represented by 32 species (three ornithischians, six sauropods and 23 theropods) from Brazil, Egypt, Lybia, Morocco, Niger, Sudan and Tunisia. These dinosaur assemblages provide fundamental data about distribution and composition of sauropods and theropods in northern Gondwana during the middle of the Cretaceous Period and confirm these assemblages to be among the most important dinosaur faunas in the north Gondwana areas.

  14. Religionsvetenskapen i övergången från den första till den andra moderniteten

    DEFF Research Database (Denmark)

    Ahlin, Lars

    2009-01-01

    Den tyske sociolog Ulrich Beck er optaget af overgangen fra den første til den anden modernitet. Han argumenterer for at denne overgang fører til at sociologiske kategorier som klasse og familie bliver zombie-kategorier. Det er kategorier skabt under den første modernitet men som stadigvæk er i...... brug i dag under den anden modernitet, til trods for at de er levende døde kategorier. I denne artikel argumenters for at kategorier, begreber, brugt inden for religionsvidenskaben, primært religionssociologien, også kan betragtes som zombie-kategorier. De begreber der diskuteres er religiøse...

  15. Nocturnality in dinosaurs inferred from scleral ring and orbit morphology.

    Science.gov (United States)

    Schmitz, Lars; Motani, Ryosuke

    2011-05-06

    Variation in daily activity patterns facilitates temporal partitioning of habitat and resources among species. Knowledge of temporal niche partitioning in paleobiological systems has been limited by the difficulty of obtaining reliable information about activity patterns from fossils. On the basis of an analysis of scleral ring and orbit morphology in 33 archosaurs, including dinosaurs and pterosaurs, we show that the eyes of Mesozoic archosaurs were adapted to all major types of diel activity (that is, nocturnal, diurnal, and cathemeral) and provide concrete evidence of temporal niche partitioning in the Mesozoic. Similar to extant amniotes, flyers were predominantly diurnal; terrestrial predators, at least partially, nocturnal; and large herbivores, cathemeral. These similarities suggest that ecology drives the evolution of diel activity patterns.

  16. A basal tyrannosauroid dinosaur from the Late Jurassic of China.

    Science.gov (United States)

    Xu, Xing; Clark, James M; Forster, Catherine A; Norell, Mark A; Erickson, Gregory M; Eberth, David A; Jia, Chengkai; Zhao, Qi

    2006-02-01

    The tyrannosauroid fossil record is mainly restricted to Cretaceous sediments of Laurasia, although some very fragmentary Jurassic specimens have been referred to this group. Here we report a new basal tyrannosauroid, Guanlong wucaii gen. et sp. nov., from the lower Upper Jurassic of the Junggar Basin, northwestern China. G. wucaii is the oldest known tyrannosauroid and shows several unexpectedly primitive pelvic features. Nevertheless, the limbs of G. wucaii share several features with derived coelurosaurs, and it possesses features shared by other coelurosaurian clades. This unusual combination of character states provides an insight into the poorly known early radiation of the Coelurosauria. Notably, the presumed predatory Guanlong has a large, fragile and highly pneumatic cranial crest that is among the most elaborate known in any non-avian dinosaur and could be comparable to some classical exaggerated ornamental traits among vertebrates.

  17. Evolution of high tooth replacement rates in sauropod dinosaurs.

    Directory of Open Access Journals (Sweden)

    Michael D D'Emic

    Full Text Available BACKGROUND: Tooth replacement rate can be calculated in extinct animals by counting incremental lines of deposition in tooth dentin. Calculating this rate in several taxa allows for the study of the evolution of tooth replacement rate. Sauropod dinosaurs, the largest terrestrial animals that ever evolved, exhibited a diversity of tooth sizes and shapes, but little is known about their tooth replacement rates. METHODOLOGY/PRINCIPAL FINDINGS: We present tooth replacement rate, formation time, crown volume, total dentition volume, and enamel thickness for two coexisting but distantly related and morphologically disparate sauropod dinosaurs Camarasaurus and Diplodocus. Individual tooth formation time was determined by counting daily incremental lines in dentin. Tooth replacement rate is calculated as the difference between the number of days recorded in successive replacement teeth. Each tooth family in Camarasaurus has a maximum of three replacement teeth, whereas each Diplodocus tooth family has up to five. Tooth formation times are about 1.7 times longer in Camarasaurus than in Diplodocus (315 vs. 185 days. Average tooth replacement rate in Camarasaurus is about one tooth every 62 days versus about one tooth every 35 days in Diplodocus. Despite slower tooth replacement rates in Camarasaurus, the volumetric rate of Camarasaurus tooth replacement is 10 times faster than in Diplodocus because of its substantially greater tooth volumes. A novel method to estimate replacement rate was developed and applied to several other sauropodomorphs that we were not able to thin section. CONCLUSIONS/SIGNIFICANCE: Differences in tooth replacement rate among sauropodomorphs likely reflect disparate feeding strategies and/or food choices, which would have facilitated the coexistence of these gigantic herbivores in one ecosystem. Early neosauropods are characterized by high tooth replacement rates (despite their large tooth size, and derived titanosaurs and

  18. Temporal and phylogenetic evolution of the sauropod dinosaur body plan

    Science.gov (United States)

    Bates, Karl T.; Mannion, Philip D.; Falkingham, Peter L.; Brusatte, Stephen L.; Hutchinson, John R.; Otero, Alejandro; Sellers, William I.; Sullivan, Corwin; Stevens, Kent A.; Allen, Vivian

    2016-03-01

    The colossal size and body plan of sauropod dinosaurs are unparalleled in terrestrial vertebrates. However, to date, there have been only limited attempts to examine temporal and phylogenetic patterns in the sauropod bauplan. Here, we combine three-dimensional computational models with phylogenetic reconstructions to quantify the evolution of whole-body shape and body segment properties across the sauropod radiation. Limitations associated with the absence of soft tissue preservation in fossils result in large error bars about mean absolute body shape predictions. However, applying any consistent skeleton : body volume ratio to all taxa does yield changes in body shape that appear concurrent with major macroevolutionary events in sauropod history. A caudad shift in centre-of-mass (CoM) in Middle Triassic Saurischia, associated with the evolution of bipedalism in various dinosaur lineages, was reversed in Late Triassic sauropodomorphs. A craniad CoM shift coincided with the evolution of quadrupedalism in the Late Triassic, followed by a more striking craniad shift in Late Jurassic-Cretaceous titanosauriforms, which included the largest sauropods. These craniad CoM shifts are strongly correlated with neck enlargement, a key innovation in sauropod evolution and pivotal to their gigantism. By creating a much larger feeding envelope, neck elongation is thought to have increased feeding efficiency and opened up trophic niches that were inaccessible to other herbivores. However, we find that relative neck size and CoM position are not strongly correlated with inferred feeding habits. Instead the craniad CoM positions of titanosauriforms appear closely linked with locomotion and environmental distributions, potentially contributing to the continued success of this group until the end-Cretaceous, with all other sauropods having gone extinct by the early Late Cretaceous.

  19. Temporal and phylogenetic evolution of the sauropod dinosaur body plan

    Science.gov (United States)

    Bates, Karl T.; Mannion, Philip D.; Falkingham, Peter L.; Brusatte, Stephen L.; Hutchinson, John R.; Otero, Alejandro; Sellers, William I.; Sullivan, Corwin; Stevens, Kent A.; Allen, Vivian

    2016-01-01

    The colossal size and body plan of sauropod dinosaurs are unparalleled in terrestrial vertebrates. However, to date, there have been only limited attempts to examine temporal and phylogenetic patterns in the sauropod bauplan. Here, we combine three-dimensional computational models with phylogenetic reconstructions to quantify the evolution of whole-body shape and body segment properties across the sauropod radiation. Limitations associated with the absence of soft tissue preservation in fossils result in large error bars about mean absolute body shape predictions. However, applying any consistent skeleton : body volume ratio to all taxa does yield changes in body shape that appear concurrent with major macroevolutionary events in sauropod history. A caudad shift in centre-of-mass (CoM) in Middle Triassic Saurischia, associated with the evolution of bipedalism in various dinosaur lineages, was reversed in Late Triassic sauropodomorphs. A craniad CoM shift coincided with the evolution of quadrupedalism in the Late Triassic, followed by a more striking craniad shift in Late Jurassic–Cretaceous titanosauriforms, which included the largest sauropods. These craniad CoM shifts are strongly correlated with neck enlargement, a key innovation in sauropod evolution and pivotal to their gigantism. By creating a much larger feeding envelope, neck elongation is thought to have increased feeding efficiency and opened up trophic niches that were inaccessible to other herbivores. However, we find that relative neck size and CoM position are not strongly correlated with inferred feeding habits. Instead the craniad CoM positions of titanosauriforms appear closely linked with locomotion and environmental distributions, potentially contributing to the continued success of this group until the end-Cretaceous, with all other sauropods having gone extinct by the early Late Cretaceous. PMID:27069652

  20. Tegn og iagttagelse. At læse Erslev efter den sproglige vending

    DEFF Research Database (Denmark)

    Simonsen, Dorthe Gert

    2001-01-01

    Historie, Historieteori, Historisk metode, Klassisk kildekritik, New Historicism, Den sproglige vending......Historie, Historieteori, Historisk metode, Klassisk kildekritik, New Historicism, Den sproglige vending...

  1. Russisk oljetransport gjennom Barentshavet : En tilfellestudie av den norske responsen

    OpenAIRE

    Aasen, Kari

    2010-01-01

    Oppgaven er en tilfellestudie av den norske responsen på økningen av russisk oljetransport gjennom Barentshavet. Oljetransporten fra Nordvest-Russland tok seg plutselig dramatisk opp i 2002, noe som kom svært overraskende på norske myndigheter. Hensikten med oppgaven har derfor vært å kartlegge den norske responsen, for å finne ut hva som har preget den. På bakgrunn av kjennetegnene ved responsen har jeg deretter forsøkt å sannsynliggjøre hvilke oppfatninger av Russland som vært dominerende. ...

  2. Den Dingen auf den Grund gehen. Meta-Modell Arbeit in der E-Mailberatung.

    Directory of Open Access Journals (Sweden)

    Stefan Schumacher

    2011-10-01

    Full Text Available Ausgehend von der Frage, wie in der schriftlichen Kommunikation Informationsklarheit und Interpretationssicherheit verbessert werden können, beschreibt der Autor das sogenannte Meta-Modell der Sprache, das auf dem Hintergrund des Sprachwissenschaftlers Noam Chomsky von den Begründern des Neurolinguistischen Programmierens (NLP vorgestellt wurde. Bandler und Grinder stellen verschiedene Formen der sprachlichen Auslassung dar, die in der Kommunikation entstehenkönnen. Der Autor streicht die Bedeutung für die Onlineberatung heraus und zeigt anhand praktischer Beispiele, wie mit dem Meta-Modell der Sprache in der Beratung gearbeitet werden kann.

  3. Radiomontagen og dens radiofoniske rødder. Om hørebilledet, den litterære tekstmontage, featuren og den moderne radiomontage

    Directory of Open Access Journals (Sweden)

    Ib Poulsen

    2001-09-01

    Full Text Available Radiomontagen og dens genrevarianter, hørebilledet og featuren har tidligere har tidligere været genstand for interesse fra især den æste- tiske og tekstanalytisk orienterede radioforskning. I denne artikel sæt- tes genren ind i en bredere kontekst, sociokulturelt og medie- og insti- tutionshistorisk. Ledetrådene i den diakrone fremstilling er dels spørgs- målet om genrens historiske og genremæssige rødder, dels en kombi- neret tekstanalytisk og receptionsæstetisk tilgang, der søger at ind- kredse de positioneringer af lytteren, radiomontagen og dens varianter tilbyder. Artiklen er baseret på grundige arkivstudier i DR og på inter- views med nogle af de ’montører’, som har bidraget til udviklingen af montagen, der i kraft af sin radiofoniske spændvidde mest vedholdende og varieret har forsøgt at udforske menneskets livssituation i den moder- ne verden, samtidig med at lytteren er blevet tilbudt en lytteposition, der prioriterer refleksion og eftertanke.

  4. Denning Ecology of Black Bears in the Great Dismal Swamp

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Available information on black bear denning ecology in southeastern wetland populations for management and conservation purposes is limited. This researcher...

  5. Polar bear den survey, Arctic National Wildlife Range

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In conjunction with the Polar Bear Research Project being supervised by Mr. Jack Lentfer of the Bureau of Sport Fisheries and Wildlife two Polar Bear den surveys...

  6. Europas Abgrund neu inszeniert - Zwischen den Zeilen Ulrich Halterns

    Directory of Open Access Journals (Sweden)

    David R. Wenger

    2006-09-01

    Full Text Available Spätestens seit der in einigen EU-Mitgliedstaaten heiß geführten Debatte um den Maastrichtvertrag (1992 und seine Weiterführung in Amsterdam (1997 hat die Integrationsfrage tiefe Gewässer der Staatsphilosophie erreicht. Was sich zuvor gleichsam abgeschirmt von der Öffentlichkeit in Expertengremien vorwiegend handelstechnischer Vereinfachung widmete, brach in Gestalt erster nationaler Referenden jäh an die politische Oberfläche. Der zumal seit den negativen Verfassungsvoten in Frankreich und den Niederlanden allgegenwärtige Diskurs über eine europäische Identität verdeutlicht auffällig, wie sehr das einstmals so pragmatisch-sachliche Vorgreifen von den vergessenen Gründungsemotionen eingeholt wird. Was man sich nämlich nicht eingestehen will: Die Grundlage der europäischen Union basiert auf einer Niederlage.

  7. Auf den Schultern von Riesen und Zwergen Einsteins unvollendete Revolution

    CERN Document Server

    Renn, Jürgen

    2006-01-01

    Dies ist die Geschichte von Einsteins unvollendeter Revolution, einer tiefgreifenden Veränderung unserer Begriffe von Raum, Zeit, Materie und Strahlung. Diese Revolution begann in Einsteins Wunderjahr 1905, wurde durch seine allgemeine Relativitätstheorie aus dem Jahre 1915 fortgesetzt und wirkt in den heutigen Versuchen der Wissenschaft, die Entstehung und das Schicksal des Universums zu verstehen, weiter. Vor dem Hintergrund einer historischen Theorie des wissenschaftlichen Fortschritts wird Einsteins bis heute nicht abgeschlossene Revolution als das Ergebnis einer langfristigen Entwicklung des Wissens verständlich. Anhand der spannenden Geschichte von Einsteins Entdeckungen wird nachvollziehbar, warum große Denker wie Einstein weiter gesehen haben als ihre Vorgänger. Sie standen nicht nur auf den Schultern von Riesen, also den wissenschaftlichen Leistungen einzelner großer Vorgänger wie Newton, sondern auch auf den Schultern von "Zwergen", dem wissenschaftlichen Wissen, dem technischen Wissen, und d...

  8. Importance of agricultural landscapes to nesting burrowing owls in the Northern Great Plains, USA

    Science.gov (United States)

    Restani, M.; Davies, J.M.; Newton, W.E.

    2008-01-01

    Anthropogenic habitat loss and fragmentation are the principle factors causing declines of grassland birds. Declines in burrowing owl (Athene cunicularia) populations have been extensive and have been linked to habitat loss, primarily the decline of black-tailed prairie dog (Cynomys ludovicianus) colonies. Development of habitat use models is a research priority and will aid conservation of owls inhabiting human-altered landscapes. From 2001 to 2004 we located 160 burrowing owl nests on prairie dog colonies on the Little Missouri National Grassland in North Dakota. We used multiple linear regression and Akaike's Information Criterion to estimate the relationship between cover type characteristics surrounding prairie dog colonies and (1) number of owl pairs per colony and (2) reproductive success. Models were developed for two spatial scales, within 600 m and 2,000 m radii of nests for cropland, crested wheatgrass (Agropyron cristatum), grassland, and prairie dog colonies. We also included number of patches as a metric of landscape fragmentation. Annually, fewer than 30% of prairie dog colonies were occupied by owls. None of the models at the 600 m scale explained variation in number of owl pairs or reproductive success. However, models at the 2,000 m scale did explain number of owl pairs and reproductive success. Models included cropland, crested wheatgrass, and prairie dog colonies. Grasslands were not included in any of the models and had low importance values, although percentage grassland surrounding colonies was high. Management that protects prairie dog colonies bordering cropland and crested wheatgrass should be implemented to maintain nesting habitat of burrowing owls. ?? 2008 Springer Science+Business Media B.V.

  9. Geochemical environmental changes and dinosaur extinction during the Cretaceous-Paleogene (K/T) transition in the Nanxiong Basin, South China: Evidence from dinosaur eggshells

    Institute of Scientific and Technical Information of China (English)

    ZHAO ZiKui; MAO XueYing; CHAI ZhiFang; YANG GaoChuang; ZHANG FuCheng; YAN Zheng

    2009-01-01

    The complex patterns of trace elements including Ir and isotope distributions in the three K/T sections of the Nanxiong Basin prove the existence of two environmental events in the latest Cretaceous and earliest Paleocene. The first geochemical environmental event occurred at about 2 Ma prior to the K/T boundary interval, where the dinosaur diversity was hardly reduced, except that a number of patho-logical eggshells appeared. The second one was larger and occurred just at and near the Creta-ceous-Paleogene (K/T) boundary. The extinction of the dinosaurs spread out within 250 ka with major extinction beginning at the boundary interval. This is even later than their extinction in Montana, North America and in India. The cause of the dinosaur extinction may be the result of a complex multiple events brought about by the coincidence of global environment change marked by multiple Ir and δ18O anomalies, and environmental poisoning characterized by other trace elements derived from the local source. Successive short-and long-term conditions of geochemically induced environmental stress negatively affected the reproductive process and thus contributed to the extinction of the dinosaurs.

  10. Evaluation Studies of the DEN-2/S-1 Vaccine.

    Science.gov (United States)

    1981-08-01

    Urbana, IL 61801). This drug was found to have antiviral activity against herpes s.mplex viruses (types I and II), vaccinia, influenza PR8...painfluenza 3, coxsackie A-21 and equine rhinovirus (Dr. Rinehart, personal communication). We have found that Didemnin A reduces plaque formation by DEN-i, DEN...3 and herpes simplex virus type 2 (see figures I and 2). Fifty percent inu- bition of plaque formation by these viruses was observed at drug

  11. Wer regiert das Intenet? - Ausschnitte aus den Veranstaltungen der Ringvorlesung

    OpenAIRE

    Schünemann, Wolf J.

    2015-01-01

    In den vergangenen Jahren, und noch einmal verstärkt mit den jüngsten Enthüllungen im sogenannten NSA-Skandal, hat sich die öffentliche Aufmerksamkeit für das Internet als Gegenstand politischen Denkens und gesellschaftlicher Regulierung erheblich gesteigert. Vor diesem Hintergrund scheint es geboten, grundlegende Fragen des gesellschaftspolitischen Umgangs mit dem Internet, vor allem auch der (zwischen-) staatlichen und transnationalen Regulierung des Netzes unter Einschluss verschiedener ge...

  12. CIOs mangler fundamentale egenskaber for at lede den digitale transformation

    DEFF Research Database (Denmark)

    Bjørn-Andersen, Niels

    2016-01-01

    CIOs er dårligt rustet til at gå i spidsen for digital disruption og innovation, advarer den internationale topforsker Joe Peppard med afsæt i analyse af mere end 200 CIO-s personligheder......CIOs er dårligt rustet til at gå i spidsen for digital disruption og innovation, advarer den internationale topforsker Joe Peppard med afsæt i analyse af mere end 200 CIO-s personligheder...

  13. Uddrag af Ph.d.-afhandlingen Den groteske modernisme

    DEFF Research Database (Denmark)

    Lübker, Henrik

    2011-01-01

    Om forholdet mellem "det groteske" og "den groteske modernisme" eksemplificeret i en læsning af E.A. Poes "The Fall of the House of Usher" og flere af Francis Bacons malerier.......Om forholdet mellem "det groteske" og "den groteske modernisme" eksemplificeret i en læsning af E.A. Poes "The Fall of the House of Usher" og flere af Francis Bacons malerier....

  14. Burrowing and avoidance behaviour in marine organisms exposed to pesticide-contaminated sediment

    DEFF Research Database (Denmark)

    Møhlenberg, Flemming; Kiørboe, Thomas

    1983-01-01

    Behavioural effects of marine sediment contaminated with pesticides (6000 ppm parathion, 200 ppm methyl parathion, 200 ppm malathion) were studied in a number of marine organisms in laboratory tests and in situ. The burrowing behaviour in Macoma baltica, Cerastoderma edule, Abra alba, Nereis...... for Crangon crangon and Solea solea, but not for Carcinus meanas and Pomatoschistus minutus. The validity of both behavioural tests was supported by in situ observations and investigations on the distribution of the species. It is concluded that both tests are useful tools in the assessment of the impact...

  15. Do brooding and polygamy behaviors exist on Cretaceous oviraptoroid dinosaurs of China: a paleobiological perspective

    Science.gov (United States)

    Yang, T.-R.; Cheng, Y.-N.; Yang, K.-M.

    2012-04-01

    Brooding, parental care, and polygamy represent three different stages in bird's reproduction. The oringin of these behaviors is still in debate. Several samples excavated from China strengthen the phylogenetic relationship between birds and dinosaurs, for example, feathered dinosaurs, paired-eggs in pelvic region of an oviraptorid dinosaur, and small theropod fossils. Previous studies in past two decades, including an oviraptor sitting on a clutch and comparison of the ratio of clutch-volume to adult-body-size between Aves and Mesozoic dinosaurs, proposed that these behaviors had appeared on some Cretaceous theropods (e.g., oviraptor and troodon). These researches also indicate the possibility of endothermy and male care first. In conclusion, this reproduction strategy might support females having more remnant energy to build a larger clutch contributed eggs from multiple females, and brooded by males only. From our cluster analysis through paleoecological perspectives, the eggs in Cretaceous oviraptor's nest should not be corporately laid by multiple females. In morphological observation, the fossilized clutches from Ganzhou, Jiangxi, Mainland China, are 2-layered interbeded with matrix of reddish-brown siltstone or clays. The inner-layer eggs are hampered from directly contacting with adult dinosaurs body. Furthermore, the blunt ends of the eggs point to the center, and incline away forming a mound-shape nest, which is completely different from those of precocial and male-caring megapode. The ornamentation of eggshell surface and microstructures from thin sections of eggs from oviraptors and ostrich (Struthioniformes) are totally different. Comparison of thickness in different part of oviraptor's egg also reveal possible physiological structure in the egg and ecological behaviors. The detailed comparison implies that the Mesozoic oviraptoroid dinosaurs hold absolutely different incubation and caring behaviors from extant birds. We propose an alternative

  16. Dental microwear reveals mammal-like chewing in the neoceratopsian dinosaur Leptoceratops gracilis

    Directory of Open Access Journals (Sweden)

    Frank J. Varriale

    2016-07-01

    Full Text Available Extensive oral processing of food through dental occlusion and orbital mandibular movement is often cited as a uniquely mammalian trait that contributed to their evolutionary success. Save for mandibular translation, these adaptations are not seen in extant archosaurs or lepidosaurs. In contrast, some ornithischian dinosaurs show evidence of precise dental occlusion, habitual intraoral trituration and complex jaw motion. To date, however, a robust understanding of the diversity of jaw mechanics within non-avian dinosaurs, and its comparison with other vertebrates, remains unrealized. Large dental batteries, well-developed dental wear facets, and robust jaws suggests that neoceratopsian (horned dinosaurs were capable chewers. But, biomechanical analyses have assumed a relatively simple, scissor-like (orthal jaw mechanism for these animals. New analyses of dental microwear, presented here, show curvilinear striations on the teeth of Leptoceratops. These features indicate a rostral to caudal orbital motion of the mandible during chewing. A rostrocaudal mandibular orbit is seen in multituberculates, haramiyid allotherians, and some rodents, and its identification in Leptoceratops gracilis is the first evidence of complex, mammal-like chewing in a ceratopsian dinosaur. The term circumpalinal is here proposed to distinguish this new style of chewing from other models of ceratopsian mastication that also involve a palinal component. This previously unrecognized complexity in dinosaurian jaw mechanics indicates that some neoceratopsian dinosaurs achieved a mammalian level of masticatory efficiency through novel adaptive solutions.

  17. Bringing dinosaurs back to life: exhibiting prehistory at the American Museum of Natural History.

    Science.gov (United States)

    Rieppel, Lukas

    2012-09-01

    This essay examines the exhibition of dinosaurs at the American Museum of Natural History during the first two decades of the twentieth century. Dinosaurs provide an especially illuminating lens through which to view the history of museum display practices for two reasons: they made for remarkably spectacular exhibits; and they rested on contested theories about the anatomy, life history, and behavior of long-extinct animals to which curators had no direct observational access. The American Museum sought to capitalize on the popularity of dinosaurs while mitigating the risks of mounting an overtly speculative display by fashioning them into a kind of mixed-media installation made of several elements, including fossilized bone, shellac, iron, and plaster. The resulting sculptures provided visitors with a vivid and lifelike imaginative experience. At the same time, curators, who were anxious to downplay the speculative nature of mounted dinosaurs, drew systematic attention to the material connection that tied individual pieces of fossilized bone to the actual past. Freestanding dinosaurs can therefore be read to have functioned as iconic sculptures that self-consciously advertised their indexical content.

  18. Dental microwear reveals mammal-like chewing in the neoceratopsian dinosaur Leptoceratops gracilis.

    Science.gov (United States)

    Varriale, Frank J

    2016-01-01

    Extensive oral processing of food through dental occlusion and orbital mandibular movement is often cited as a uniquely mammalian trait that contributed to their evolutionary success. Save for mandibular translation, these adaptations are not seen in extant archosaurs or lepidosaurs. In contrast, some ornithischian dinosaurs show evidence of precise dental occlusion, habitual intraoral trituration and complex jaw motion. To date, however, a robust understanding of the diversity of jaw mechanics within non-avian dinosaurs, and its comparison with other vertebrates, remains unrealized. Large dental batteries, well-developed dental wear facets, and robust jaws suggests that neoceratopsian (horned) dinosaurs were capable chewers. But, biomechanical analyses have assumed a relatively simple, scissor-like (orthal) jaw mechanism for these animals. New analyses of dental microwear, presented here, show curvilinear striations on the teeth of Leptoceratops. These features indicate a rostral to caudal orbital motion of the mandible during chewing. A rostrocaudal mandibular orbit is seen in multituberculates, haramiyid allotherians, and some rodents, and its identification in Leptoceratops gracilis is the first evidence of complex, mammal-like chewing in a ceratopsian dinosaur. The term circumpalinal is here proposed to distinguish this new style of chewing from other models of ceratopsian mastication that also involve a palinal component. This previously unrecognized complexity in dinosaurian jaw mechanics indicates that some neoceratopsian dinosaurs achieved a mammalian level of masticatory efficiency through novel adaptive solutions.

  19. Avian Influenza Virus for Phylogenetic Tree Reconstrction Based on Extension Burrows-Wheeler%基于扩展Burrows-Wheeler算法重构禽流感病毒的进化树

    Institute of Scientific and Technical Information of China (English)

    夏阳; 白凤兰; 刘立伟

    2014-01-01

    基于核苷酸的物理化学性质,利用扩展Burrows-Wheeler算法和Burrows-Wheeler相似性分布,对80种H5NI病毒的DNA序列的HA片段进行相似性比较,同时构建序列进化树,得到较好的结果.通过分析禽流感病毒之间的相似度关系,可为研究禽流感区域蔓延的特点提供一定的理论依据.

  20. Estimating animal populations and body sizes from burrows: Marine ecologists have their heads buried in the sand

    Science.gov (United States)

    Schlacher, Thomas A.; Lucrezi, Serena; Peterson, Charles H.; Connolly, Rod M.; Olds, Andrew D.; Althaus, Franziska; Hyndes, Glenn A.; Maslo, Brooke; Gilby, Ben L.; Leon, Javier X.; Weston, Michael A.; Lastra, Mariano; Williams, Alan; Schoeman, David S.

    2016-06-01

    Most ecological studies require knowledge of animal abundance, but it can be challenging and destructive of habitat to obtain accurate density estimates for cryptic species, such as crustaceans that tunnel deeply into the seafloor, beaches, or mudflats. Such fossorial species are, however, widely used in environmental impact assessments, requiring sampling techniques that are reliable, efficient, and environmentally benign for these species and environments. Counting and measuring the entrances of burrows made by cryptic species is commonly employed to index population and body sizes of individuals. The fundamental premise is that burrow metrics consistently predict density and size. Here we review the evidence for this premise. We also review criteria for selecting among sampling methods: burrow counts, visual censuses, and physical collections. A simple 1:1 correspondence between the number of holes and population size cannot be assumed. Occupancy rates, indexed by the slope of regression models, vary widely between species and among sites for the same species. Thus, 'average' or 'typical' occupancy rates should not be extrapolated from site- or species specific field validations and then be used as conversion factors in other situations. Predictions of organism density made from burrow counts often have large uncertainty, being double to half of the predicted mean value. Whether such prediction uncertainty is 'acceptable' depends on investigators' judgements regarding the desired detectable effect sizes. Regression models predicting body size from burrow entrance dimensions are more precise, but parameter estimates of most models are specific to species and subject to site-to-site variation within species. These results emphasise the need to undertake thorough field validations of indirect census techniques that include tests of how sensitive predictive models are to changes in habitat conditions or human impacts. In addition, new technologies (e.g. drones

  1. Do leucocytes reflect condition in nestling burrowing parrots Cyanoliseus patagonus in the wild?

    Science.gov (United States)

    Masello, Juan F; Choconi, R Gustavo; Helmer, Matthias; Kremberg, Thomas; Lubjuhn, Thomas; Quillfeldt, Petra

    2009-02-01

    The different leucocyte types are an important part of the immune system. Thus, they have been used in ecological studies to assess immune function and physiological stress in wild birds. It is generally assumed that increased stress and decreased condition are associated with an increase in the ratio of heterophils to lymphocytes, the H/L ratio. We studied leucocyte profiles in relation to body condition in nestling Burrowing Parrots (Cyanoliseus patagonus) in North-eastern Patagonia, Argentina. As in other wild parrots, heterophils were the most numerous leucocyte type, suggesting strong investment into innate immunity. Leucocyte profiles did not change with the age, while nestlings in better body condition increased the number of heterophils. Because the number of lymphocytes was independent of body condition, as a result we observed a positive correlation between body condition and the H/L ratio. The total number of leucocytes relative to erythrocytes increased in nestlings in better body condition, indicating a larger overall investment into immune function in well-nourished nestlings. The observed heterophilic profiles of nestling Burrowing Parrots together with the positive relationship between H/L ratio and body condition may indicate a favoured investment in a robust innate immunity that reduces the risk of infection taking hold in these long-lived birds.

  2. Real estate ads in Emei music frog vocalizations: female preference for calls emanating from burrows.

    Science.gov (United States)

    Cui, Jianguo; Tang, Yezhong; Narins, Peter M

    2012-06-23

    During female mate choice, both the male's phenotype and resources (e.g. his nest) contribute to the chooser's fitness. Animals other than humans are not known to advertise resource characteristics to potential mates through vocal communication; although in some species of anurans and birds, females do evaluate male qualities through vocal communication. Here, we demonstrate that calls of the male Emei music frog (Babina dauchina), vocalizing from male-built nests, reflect nest structure information that can be recognized by females. Inside-nest calls consisted of notes with energy concentrated at lower frequency ranges and longer note durations when compared with outside-nest calls. Centre frequencies and note durations of the inside calls positively correlate with the area of the burrow entrance and the depth of the burrow, respectively. When given a choice between outside and inside calls played back alternately, more than 70 per cent of the females (33/47) chose inside calls. These results demonstrate that males of this species faithfully advertise whether or not they possess a nest to potential mates by vocal communication, which probably facilitates optimal mate selection by females. These results revealed a novel function of advertisement calls, which is consistent with the wide variation in both call complexity and social behaviour within amphibians.

  3. The antenna of a burrowing dragonfly larva, Onychogomphus forcipatus (Anisoptera, Gomphidae).

    Science.gov (United States)

    Rebora, Manuela; Piersanti, Silvana; Salerno, Gianandrea; Gorb, Stanislav

    2015-11-01

    The larva of the dragonfly Onychogomphus forcipatus (Anisoptera, Gomphidae) has a burrowing lifestyle and antennae composed of four short and broad segments (scape, pedicel and a two-segmented flagellum). The present ultrastructural investigation revealed that different sensilla and one gland are located on the antenna. There is a great diversity of mechanoreceptors of different kinds. In particular club-shaped sensilla, sensilla chaetica, and tree-like sensilla show the typical structure of bristles, the most common type of mechanoreceptors, usually responding to direct touch, while numerous long thin thorny trichoid sensilla show a morphology recalling the structure of filiform hair mechanoreceptors. The latter ones are presumably important in larval Odonata for current detection and rheotactic orientation, especially in a burrowing species. On the smooth apical cuticle of the second flagellar segment, three structures are visible: (1) a small ellipsoidal pit hosting a convoluted peg, the morphology of which resembles that of a typical chemoreceptor (even if pores are lacking), (2) a couple of small pits (not investigated under TEM), and (3) one wide depression with spherical structures, the internal morphology of which lets us assume that it is a gland with unknown function. This is the first report of an antennal gland in palaeopteran insects.

  4. [The supra-occipital bone in cetaceans and burrowing rodents. morphological convergence induced by the post-cephalic pole?].

    Science.gov (United States)

    Courant, F; Marchand, D

    2000-02-01

    A comparative study of the cranial morphologies of cetaceans and of rodents that use their incisors for burrowing brings out morphological convergences concerning the supra-occipital bone. These phyletically very remote groups are both subject to the same mechanical constraint, viz. the need for the spinal column to be aligned with the anteroposterior axis of the skull. This constraint, which is related to swimming in cetaceans and burrowing in rodents, entails three major points of convergence: 1) a clearly backward facing foramen magnum; 2) a shortened or even greatly shortened neck, sometimes with cervical vertebrae fused together; and 3) an uprighted or even forward tilted supra-occipital bone.

  5. Artificial warthog burrows used to sample adult and immature tsetse (Glossina spp in the Zambezi Valley of Zimbabwe.

    Directory of Open Access Journals (Sweden)

    John W Hargrove

    2015-03-01

    Full Text Available The biology of adult tsetse (Glossina spp, vectors of trypanosomiasis in Africa, has been extensively studied - but little is known about larviposition in the field.In September-November 1998, in the hot-dry season in Zimbabwe's Zambezi Valley, we used artificial warthog burrows to capture adult females as they deposited larvae. Females were subjected to ovarian dissection and were defined as perinatal flies, assumed to have entered burrows to larviposit, if oocyte sizes indicated >95% pregnancy completion. Perinatal flies were defined as full-term pregnant if there was a late third instar larva in utero, or postpartum if the uterus was empty. All other females were defined as pre-full-term pregnant (pre-FT. Of 845 G. m. morsitans captured, 91% (765 were female and 295/724 (41% of females dissected were perinatal flies. By contrast, of 2805 G. pallidipes captured only 71% (2003 were female and only 33% (596/1825 of females were perinatal. Among all perinatal females 67% (596/891 were G. pallidipes. Conversely, in burrows not fitted with traps - such that flies were free to come and go - 1834 (59% of pupae deposited were G. m. morsitans and only 1297 (41% were G. pallidipes. Thus, while more full-term pregnant G. pallidipes enter burrows, greater proportions of G. m. morsitans larviposit in them, reflecting a greater discrimination among G. pallidipes in choosing larviposition sites. Catches of males and pre-FT females increased strongly with temperatures above 32°C, indicating that these flies used burrows as refuges from high ambient temperatures. Conversely, catches of perinatal females changed little with maximum temperature but declined from late September through November: females may anticipate that burrows will be inundated during the forthcoming wet season. Ovarian age distributions of perinatal and pre-FT females were similar, consistent with all ages of females larvipositing in burrows with similar probability.Artificial warthog

  6. Measuring the contribution of benthic ecosystem engineering species to the ecosystem services of an estuary: A case study of burrowing shrimps in Yaquina Estuary, Oregon - April 2009

    Science.gov (United States)

    Burrowing shrimps are regarded as ecosystem engineering species in many coastal ecosystems worldwide, including numerous estuaries of the west coast of North America (Baja California to British Columbia). In estuaries of the U.S. Pacific Northwest, two species of large burrowing...

  7. Measuring the contribution of benthic ecosystem engineering species to the ecosystem services of an estuary: A case study of burrowing shrimps in Yaquina Estuary, Oregon

    Science.gov (United States)

    Burrowing shrimps are regarded as ecosystem engineering species in many coastal ecosystems worldwide, including numerous estuaries of the west coast of North America (Baja California to British Columbia). In estuaries of the U.S. Pacific Northwest, two species of large burrowing...

  8. A new primitive Neornithischian dinosaur from the Jurassic of Patagonia with gut contents

    Science.gov (United States)

    Salgado, Leonardo; Canudo, José I.; Garrido, Alberto C.; Moreno-Azanza, Miguel; Martínez, Leandro C. A.; Coria, Rodolfo A.; Gasca, José M.

    2017-02-01

    We describe a new species of an ornithischian dinosaur, Isaberrysaura mollensis gen. et sp. nov. The specimen, consisting in an almost complete skull and incomplete postcranium was collected from the marine-deltaic deposits of the Los Molles Formation (Toarcian-Bajocian), being the first reported dinosaur for this unit, one of the oldest from Neuquén Basin, and the first neornithischian dinosaur known from the Jurassic of South America. Despite showing a general stegosaurian appearance, the extensive phylogenetic analysis carried out depicts Isaberrysaura mollensis gen. et sp. nov. as a basal ornithopod, suggesting that both Thyreophora and neornithischians could have achieved significant convergent features. The specimen was preserved articulated and with some of its gut content place in the middle-posterior part of the thoracic cavity. Such stomach content was identified as seeds, most of them belonging to the Cycadales group. This finding reveals a possible and unexpected role of this ornithischian species as seed-dispersal agent.

  9. The oldest North American pachycephalosaurid and the hidden diversity of small-bodied ornithischian dinosaurs.

    Science.gov (United States)

    Evans, David C; Schott, Ryan K; Larson, Derek W; Brown, Caleb M; Ryan, Michael J

    2013-01-01

    Taphonomic biases dictate how organisms are represented in the fossil record, but their effect on studies of vertebrate diversity dynamics is poorly studied. In contrast to the high diversity and abundance of small-bodied animals in extant ecosystems, small-bodied dinosaurs are less common than their large-bodied counterparts, but it is unclear whether this reflects unique properties of dinosaurian ecosystems or relates to taphonomic biases. A new, fully domed pachycephalosaurid dinosaur, Acrotholus audeti, from the Santonian of Alberta predates incompletely domed taxa, and provides important new information on pachycephalosaur evolution and the completeness of the ornithischian fossil record. Here we provide the first empirical evidence that the diversity of small-bodied ornithischian dinosaurs is strongly underestimated based on ghost lineages and the high proportion of robust and diagnostic frontoparietal domes compared with other pachycephalosaur fossils. This suggests preservational biases have a confounding role in attempts to decipher vertebrate palaeoecology and diversity dynamics through the Mesozoic.

  10. A new long-necked 'sauropod-mimic' stegosaur and the evolution of the plated dinosaurs.

    Science.gov (United States)

    Mateus, Octávio; Maidment, Susannah C R; Christiansen, Nicolai A

    2009-05-22

    Stegosaurian dinosaurs have a quadrupedal stance, short forelimbs, short necks, and are generally considered to be low browsers. A new stegosaur, Miragaia longicollum gen. et sp. nov., from the Late Jurassic of Portugal, has a neck comprising at least 17 cervical vertebrae. This is eight additional cervical vertebrae when compared with the ancestral condition seen in basal ornithischians such as Scutellosaurus. Miragaia has a higher cervical count than most of the iconically long-necked sauropod dinosaurs. Long neck length has been achieved by 'cervicalization' of anterior dorsal vertebrae and probable lengthening of centra. All these anatomical features are evolutionarily convergent with those exhibited in the necks of sauropod dinosaurs. Miragaia longicollum is based upon a partial articulated skeleton, and includes the only known cranial remains from any European stegosaur. A well-resolved phylogeny supports a new clade that unites Miragaia and Dacentrurus as the sister group to Stegosaurus; this new topology challenges the common view of Dacentrurus as a basal stegosaur.

  11. Dinosaur evolution. Sustained miniaturization and anatomical innovation in the dinosaurian ancestors of birds.

    Science.gov (United States)

    Lee, Michael S Y; Cau, Andrea; Naish, Darren; Dyke, Gareth J

    2014-08-01

    Recent discoveries have highlighted the dramatic evolutionary transformation of massive, ground-dwelling theropod dinosaurs into light, volant birds. Here, we apply Bayesian approaches (originally developed for inferring geographic spread and rates of molecular evolution in viruses) in a different context: to infer size changes and rates of anatomical innovation (across up to 1549 skeletal characters) in fossils. These approaches identify two drivers underlying the dinosaur-bird transition. The theropod lineage directly ancestral to birds undergoes sustained miniaturization across 50 million years and at least 12 consecutive branches (internodes) and evolves skeletal adaptations four times faster than other dinosaurs. The distinct, prolonged phase of miniaturization along the bird stem would have facilitated the evolution of many novelties associated with small body size, such as reorientation of body mass, increased aerial ability, and paedomorphic skulls with reduced snouts but enlarged eyes and brains.

  12. A new sauropod dinosaur from the Middle Jurassic of the United Kingdom.

    Science.gov (United States)

    Manning, Phillip L; Egerton, Victoria M; Romano, Mike

    2015-01-01

    A new record of a sauropodomorph dinosaur is here described from the Middle Jurassic (Aalenian) Saltwick Formation of Whitby (Yorkshire), UK. A single caudal vertebra represents an early sauropodomorph and signifies the earliest recognised eusauropod dinosaur from the United Kingdom. The absence of pleurocoels and a narrow, dorsoventrally deep, but craniocaudally short centrum, suggests a primitive sauropodomorph. Distinct spinopostzygopophyseal laminae rise from the lateral margins of the postzygapophyses and pass caudally along what remains of the neural spine, a character unique to a subgroup of sauropods that includes Barapasaurus, Omeisaurus and other neosauropods and eusauropods. The lack of phylogenetically robust characters in sauropod caudal vertebrae usually makes it difficult to establish affinities, but the absence of mild procoely excludes this specimen from both Diplodocoidea and Lithostrotia. The vertebra cannot be further distinguished from those of a wide range of basal sauropods, cetiosaurids and basal macronarians. However, this plesiomorphic vertebra still signifies the earliest stratigraphic occurrence for a British sauropod dinosaur.

  13. A New Theropod Dinosaur from the Middle Jurassic of Lufeng, Yunnan, China

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-chun; Philip J.CURRIE; DONG Zhiming; PAN Shigang; WANG Tao

    2009-01-01

    A new theropod dinosaur,Shidaisaurusjinae gen.et sp.nov.,has been described on the basis of an incomplete skeleton.The specimen was found near the base of the Upper Lufeng Formation(early Middle Jurassic)in Yunnan,China.It is the first theropod dinosaur from the Middle Jurassic of Yunnan.Shidaisaurus jinae is distinguishable from other Jurassic theropods by certain features from the braincase,axis,and pelvic girdle.The absence of any pleurocoels in the axis or in any anterior dorsal vertebrae suggests that the new Lufeng theropod is relatively primitive and more plesiomorphic than most of the Middle to Late Jurassic theropods from China.Most Chinese taxa of Jurassic theropod dinosaurs have not been well described;a further detailed study will be necessary for us to determine their phylogenetic relationships with Shidaisaurus jinae.

  14. A new sauropod dinosaur from the Middle Jurassic of the United Kingdom.

    Directory of Open Access Journals (Sweden)

    Phillip L Manning

    Full Text Available A new record of a sauropodomorph dinosaur is here described from the Middle Jurassic (Aalenian Saltwick Formation of Whitby (Yorkshire, UK. A single caudal vertebra represents an early sauropodomorph and signifies the earliest recognised eusauropod dinosaur from the United Kingdom. The absence of pleurocoels and a narrow, dorsoventrally deep, but craniocaudally short centrum, suggests a primitive sauropodomorph. Distinct spinopostzygopophyseal laminae rise from the lateral margins of the postzygapophyses and pass caudally along what remains of the neural spine, a character unique to a subgroup of sauropods that includes Barapasaurus, Omeisaurus and other neosauropods and eusauropods. The lack of phylogenetically robust characters in sauropod caudal vertebrae usually makes it difficult to establish affinities, but the absence of mild procoely excludes this specimen from both Diplodocoidea and Lithostrotia. The vertebra cannot be further distinguished from those of a wide range of basal sauropods, cetiosaurids and basal macronarians. However, this plesiomorphic vertebra still signifies the earliest stratigraphic occurrence for a British sauropod dinosaur.

  15. Footprints of large theropod dinosaurs and implications on the age of Triassic biotas from Southern Brazil

    Science.gov (United States)

    da Silva, Rafael Costa; Barboni, Ronaldo; Dutra, Tânia; Godoy, Michel Marques; Binotto, Raquel Barros

    2012-11-01

    Dinosaur footprints found in an outcrop of the Caturrita Formation (Rio Grande do Sul State, Southern Brazil), associated with a diverse and well preserved record of fauna and flora, reopen the debate about its exclusive Triassic age. The studied footprints were identified as Eubrontes isp. and are interpreted as having been produced by large theropod dinosaurs. The morphological characteristics and dimensions of the footprints are more derived than those commonly found in the Carnian-Norian, and are more consistent with those found during the Rhaetian-Jurassic. The trackmaker does not correspond to any type of dinosaur yet known from Triassic rocks of Brazil. Recent studies with the paleofloristic content of this unit also support a more advanced Rhaetian or even Jurassic age for this unit.

  16. A Decade of 21st-Century Dinosaur Research at IVPP

    Institute of Scientific and Technical Information of China (English)

    Corwin Sullivan

    2010-01-01

    @@ In the first decade of the 21st century,a larger number of important new dinosaur specimens have come from China than from any other country.The Institute of Vertebrate Paleontology and Paleoanthropology(IVPP)has been at the forefront of the scientific effort to document and analyze these fossils,in collaboration with a wide range of other institutions in China and around the world.Recently discovered Chinese specimens,described by IVPP researchers and their collaborators,have shed considerable new light on the evolution of several important dinosaur groups and on various aspects of dinosaur biology.Some of the findings of these studies would have seemed even twenty or thirty years ago to be closer to the realm of science fiction than paleontological reality.

  17. New developmental evidence clarifies the evolution of wrist bones in the dinosaur-bird transition.

    Science.gov (United States)

    Botelho, João Francisco; Ossa-Fuentes, Luis; Soto-Acuña, Sergio; Smith-Paredes, Daniel; Nuñez-León, Daniel; Salinas-Saavedra, Miguel; Ruiz-Flores, Macarena; Vargas, Alexander O

    2014-09-01

    From early dinosaurs with as many as nine wrist bones, modern birds evolved to develop only four ossifications. Their identity is uncertain, with different labels used in palaeontology and developmental biology. We examined embryos of several species and studied chicken embryos in detail through a new technique allowing whole-mount immunofluorescence of the embryonic cartilaginous skeleton. Beyond previous controversy, we establish that the proximal-anterior ossification develops from a composite radiale+intermedium cartilage, consistent with fusion of radiale and intermedium observed in some theropod dinosaurs. Despite previous claims that the development of the distal-anterior ossification does not support the dinosaur-bird link, we found its embryonic precursor shows two distinct regions of both collagen type II and collagen type IX expression, resembling the composite semilunate bone of bird-like dinosaurs (distal carpal 1+distal carpal 2). The distal-posterior ossification develops from a cartilage referred to as "element x," but its position corresponds to distal carpal 3. The proximal-posterior ossification is perhaps most controversial: It is labelled as the ulnare in palaeontology, but we confirm the embryonic ulnare is lost during development. Re-examination of the fossil evidence reveals the ulnare was actually absent in bird-like dinosaurs. We confirm the proximal-posterior bone is a pisiform in terms of embryonic position and its development as a sesamoid associated to a tendon. However, the pisiform is absent in bird-like dinosaurs, which are known from several articulated specimens. The combined data provide compelling evidence of a remarkable evolutionary reversal: A large, ossified pisiform re-evolved in the lineage leading to birds, after a period in which it was either absent, nonossified, or very small, consistently escaping fossil preservation. The bird wrist provides a modern example of how developmental and paleontological data illuminate

  18. Maximal aerobic and anaerobic power generation in large crocodiles versus mammals: implications for dinosaur gigantothermy.

    Directory of Open Access Journals (Sweden)

    Roger S Seymour

    Full Text Available Inertial homeothermy, the maintenance of a relatively constant body temperature that occurs simply because of large size, is often applied to large dinosaurs. Moreover, biophysical modelling and actual measurements show that large crocodiles can behaviourally achieve body temperatures above 30°C. Therefore it is possible that some dinosaurs could achieve high and stable body temperatures without the high energy cost of typical endotherms. However it is not known whether an ectothermic dinosaur could produce the equivalent amount of muscular power as an endothermic one. To address this question, this study analyses maximal power output from measured aerobic and anaerobic metabolism in burst exercising estuarine crocodiles, Crocodylusporosus, weighing up to 200 kg. These results are compared with similar data from endothermic mammals. A 1 kg crocodile at 30°C produces about 16 watts from aerobic and anaerobic energy sources during the first 10% of exhaustive activity, which is 57% of that expected for a similarly sized mammal. A 200 kg crocodile produces about 400 watts, or only 14% of that for a mammal. Phosphocreatine is a minor energy source, used only in the first seconds of exercise and of similar concentrations in reptiles and mammals. Ectothermic crocodiles lack not only the absolute power for exercise, but also the endurance, that are evident in endothermic mammals. Despite the ability to achieve high and fairly constant body temperatures, therefore, large, ectothermic, crocodile-like dinosaurs would have been competitively inferior to endothermic, mammal-like dinosaurs with high aerobic power. Endothermy in dinosaurs is likely to explain their dominance over mammals in terrestrial ecosystems throughout the Mesozoic.

  19. Maximal aerobic and anaerobic power generation in large crocodiles versus mammals: implications for dinosaur gigantothermy.

    Science.gov (United States)

    Seymour, Roger S

    2013-01-01

    Inertial homeothermy, the maintenance of a relatively constant body temperature that occurs simply because of large size, is often applied to large dinosaurs. Moreover, biophysical modelling and actual measurements show that large crocodiles can behaviourally achieve body temperatures above 30°C. Therefore it is possible that some dinosaurs could achieve high and stable body temperatures without the high energy cost of typical endotherms. However it is not known whether an ectothermic dinosaur could produce the equivalent amount of muscular power as an endothermic one. To address this question, this study analyses maximal power output from measured aerobic and anaerobic metabolism in burst exercising estuarine crocodiles, Crocodylusporosus, weighing up to 200 kg. These results are compared with similar data from endothermic mammals. A 1 kg crocodile at 30°C produces about 16 watts from aerobic and anaerobic energy sources during the first 10% of exhaustive activity, which is 57% of that expected for a similarly sized mammal. A 200 kg crocodile produces about 400 watts, or only 14% of that for a mammal. Phosphocreatine is a minor energy source, used only in the first seconds of exercise and of similar concentrations in reptiles and mammals. Ectothermic crocodiles lack not only the absolute power for exercise, but also the endurance, that are evident in endothermic mammals. Despite the ability to achieve high and fairly constant body temperatures, therefore, large, ectothermic, crocodile-like dinosaurs would have been competitively inferior to endothermic, mammal-like dinosaurs with high aerobic power. Endothermy in dinosaurs is likely to explain their dominance over mammals in terrestrial ecosystems throughout the Mesozoic.

  20. Reanalysis of "Raptorex kriegsteini": a juvenile tyrannosaurid dinosaur from Mongolia.

    Science.gov (United States)

    Fowler, Denver W; Woodward, Holly N; Freedman, Elizabeth A; Larson, Peter L; Horner, John R

    2011-01-01

    The carnivorous Tyrannosauridae are among the most iconic dinosaurs: typified by large body size, tiny forelimbs, and massive robust skulls with laterally thickened teeth. The recently described small-bodied tyrannosaurid Raptorex kreigsteini is exceptional as its discovery proposes that many of the distinctive anatomical traits of derived tyrannosaurids were acquired in the Early Cretaceous, before the evolution of large body size. This inference depends on two core interpretations: that the holotype (LH PV18) derives from the Lower Cretaceous of China, and that despite its small size, it is a subadult or young adult. Here we show that the published data is equivocal regarding stratigraphic position and that ontogenetic reanalysis shows there is no reason to conclude that LH PV18 has reached this level of maturity. The probable juvenile status of LH PV18 makes its use as a holotype unreliable, since diagnostic features of Raptorex may be symptomatic of its immature status, rather than its actual phylogenetic position. These findings are consistent with the original sale description of LH PV18 as a juvenile Tarbosaurus from the Upper Cretaceous of Mongolia. Consequently, we suggest that there is currently no evidence to support the conclusion that tyrannosaurid skeletal design first evolved in the Early Cretaceous at small body size.