962 resultados para Geological and Natural History Survey of Minnesota


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Just as there are seashells on Mt. Everest, there is an exceptional wealth of fossil remains of marine organisms preserved in the chalk of western Kansas. This Cretaceous-aged rock, and the fossils therein, were deposited at a time when a great sea cut northward across the interior of the continent around 85 million years ago, inspiring the provocative title of Everhart's book. The title is true to its subject: documentation of the Cretaceous fossils of western Kansas, their geographic and stratigraphic occurrences, and the inferences that paleontologists can make about how the organisms represented by these fossils may have once lived and interacted with one another.

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Non-myrmecophilous lepidopteran larvae using plants bearing ant attractants such as extrafloral nectaries are good models for studying morphological and behavioural mechanisms against ant predation. Udranomia spitzi (Hesperiidae) is a butterfly whose larvae feed on leaves of Ouratea spectabilis (Ochnaceae), a plant with extrafloral nectaries. We described the early stages of U. spitzi, and used field observations and experiments to investigate the defensive strategies of caterpillars against predatory ants. Larvae pass through five instars and pupation occurs inside larval leaf shelters. Ant-exclusion experiments revealed that the presence of ants did not affect significantly caterpillar survival. Predation experiments showed that vulnerability to ant predation decreased with increase in larval size. The present study showed that predatory ants are not as relevant as demonstrated for other systems, and also illustrates how observational data and field experiments can contribute to a better understanding of the biology and ecology of a species of interest.

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Immatures of the Phelypera schuppeli (Boheman, 1834) (Curculionidae; Hyperinae; Cepurini) are described, illustrated and compared with available descriptions of larvae and pupae of Hyperini. Immatures and adults from midwest (Dourados, Mato Grosso do Sul; Pirenopolis, Goias) and southeast Brazil (Bauru, Sao Paulo) were found on leaves of the host plant, Pachira aquatica Aubl. (Malvaceae, formerly Bombacaceae), a tree used as an ornamental plant in many Brazilian frost-free cities. Larvae of P. schuppeli are exophytic, brightly colored, eruciform and possess abdominal ambulatory ampullae, resembling larvae of Lepidoptera. Mature larvae can spin globular lattice-like cocoons where pupation takes place. Data in the field and under laboratory conditions confirmed previously published biological observations on P. schuppeli. Additional information about defensive behaviors, process of cocoon construction and natural enemies, such as the larval predator Supputius cinticeps (Stal, 1860) (Hemiptera: Pentatomidae) and the prepupal and pupal parasitoid Jaliscoa nudipennis Boucek, 1993 (Hymenoptera: Pteromalidae), are reported.

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Toxoplasma gondii is a protozoan parasite that infects humans and other warm-blooded animals; it uses feral and domestic cats as the definitive hosts. Neospora caninum is a protozoan parasite of animals whose life cycle is very similar to T. gondii but uses canids as definitive hosts. Small rodents play an important role in the life cycle of T. gondii, and a few findings indicated that they may be natural intermediate hosts for N. caninum. The present study was aimed at identifying infections by T. gondii and N. caninum in urban rodents. Infections by T. gondii were quantified using isolation of the parasite by bioassay in mice; molecular methods were also used for both parasites. Overall, 217 rodents were captured. Brain and heart tissues of all rodents were bioassayed in mice for the detection of T. gondii infection. Brain and heart tissues of 121 rodents had the DNA extracted for molecular analysis. Toxoplasma gondii was isolated by bioassay from a single rodent. From the 121 rodents tested for the presence of T. gondii DNA, 2 animals were positive. In contrast, DNA of N. caninum was not detected in any of the samples. In conclusion, the surveys of N. caninum and T. gondii infection in Rattus rattus, Rattus norvegicus, and Mus musculus captured in urban areas of Sao Paulo reveal a striking low frequency of occurrence of these infections.

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ZusammenfassungSpätarchaische Sedimentgesteine (ca. 2,65 Milliarden Jahre alt) wurden in Grünsteingürteln des Simbabwe Kratons untersucht. In dem Belingwe Grünsteingürtel ist granitoides Grundgebirge von einer allochthonen Einheit aus vulkanischen Gesteinen und Vorlandbeckensedimenten überlagert. Die sedimentäre Abfolge besteht aus Flachwasserkalken und Turbiditen. Unterschiedliche Faziestypen der Kalksteine sind in sedimentäre Verflachungszyklen angeordnet. Eustatische Meeresspiegelschwankungen werden als Ursache der zyklischen Sedimentation angenommen. Sedimentologische, geochemische und strukturelle Analysen zeigen die Bedeutung horizontal-tektonischer Prozesse für die Entstehung dieses Grünsteingürtels an.Sedimentgesteine des Midlands Grünsteingürtels lagern zwischen ozeanischen, mafischen Vulkaniten und kontinentalen, granitoiden Gneisen. Die Art der Abfolge sedimentärer Fazies, beginnend mit Turbiditen und überlagert von flachmarinen Schelfsedimenten und alluvialen Ablagerungen, sowie geologische und geochemische Hinweise aus den benachbarten Gesteinsserien lassen auf Ablagerung während der Kollision zwischen einem ozeanischen Plateau/Inselbogen und einem kontinentalen Krustenfragmentes schließen.In dem Bindura-Shamva Grünsteingürtel können zwei Sedimentgesteinseinheiten unterschieden werden, eine alluvial—flachmarine Abfolge und eine tiefmarin—fluviatile Abfolge. Extensionstektonik verursachte wahrscheinlich die Bildung des Sedimentbeckens. Die spätere Phase der Beckenbildung war jedoch ähnlich jener in modernen Vorlandbecken.Schichtparallele Eisensteinhorizonte sind häufig entlang von Sediment-Vulkanit-Kontakten zu finden. Diese Gesteine werden als silifizierte und von Sulfiden imprägnierte Scherzonen interpretiert. Syntektonische hydrothermale Alteration von Gesteinen entlang der Störungszonen führte zur Bildung dieser 'tektonischen Eisensteine'.

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This article examines the role of domestic spaces and images in mid-nineteenth-century science writing for children. Analyses of John Mill’s The Fossil Spirit, A.L.O.E.’s Fairy Frisket, John Cargill Brough’s The Fairy Tales of Science, Annie Carey’s “Autobiography of a Lump of Coal,” and an assortment of boxed games reveal a variety of ways in which overwhelming scientific concepts are domesticated. Moreover, juvenile science literature contributes this appeasing domestication to the broader scientific discourse, consistently framing natural history in terms of human experience.

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To document the progression of a break in the photoreceptor inner segment/outer segment (IS/OS) junction layer and its functional correlates over time in the natural history of type 2 idiopathic macular telangiectasia (type 2 MacTel).

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The pathogenesis of Graves' ophthalmopathy has not been yet clarified, and from a therapeutic standpoint Graves' ophthalmopathy remains an enigma. The natural course and effects of different treatment regimens are poorly documented.

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All students in the United States of America are required to take science. But what if there is not a science, but in fact a number of sciences? Could every culture, perhaps every different grouping of people, create its own science? This report describes a preliminary survey, the goal of which is to improve the teaching of science at American Indian Opportunities and Industrialization Center in Minneapolis, Minnesota by beginning to understand the differences between Western and American Indian sciences.

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Analyses of pollen, macrofossils and microscopic charcoal in the sediment of a small sub-alpine lake (Karakol, Kyrgyzstan) provide new data to reconstruct the vegetation history of the Kungey Alatau spruce forest during the late-Holocene, i.e. the past 4,000 years. The pollen data suggest that Picea schrenkiana F. and M. was the dominant tree in this region from the beginning of the record. The pollen record of pronounced die-backs of the forests, along with lithostratigraphical evidence, points to possible climatic cooling (and/or drying) around 3,800 cal year B.P., and between 3,350 and 2,520 cal year B.P., with a culmination at 2,800-2,600 cal B.P., although stable climatic conditions are reported for this region for the past 3,000-4,000 years in previous studies. From 2,500 to 190 cal year B.P. high pollen values of P. schrenkiana suggest rather closed and dense forests under the environmental conditions of that time. A marked decline in spruce forests occurred with the onset of modern human activities in the region from 190 cal year B.P. These results show that the present forests are anthropogenically reduced and represent only about half of their potential natural extent. As P. schrenkiana is a species endemic to the western Tien Shan, it is most likely that its refugium was confined to this region. However, our palaeoecological record is too recent to address this hypothesis thoroughly.