965 resultados para DANISH LAKES


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This monthly report from the Iowa Department of Natural Resources is about the water quality management of Iowa's rivers, streams and lakes.

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This monthly report from the Iowa Department of Natural Resources is about the water quality management of Iowa's rivers, streams and lakes.

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This monthly report from the Iowa Department of Natural Resources is about the water quality management of Iowa's rivers, streams and lakes.

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This monthly report from the Iowa Department of Natural Resources is about the water quality management of Iowa's rivers, streams and lakes.

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This monthly report from the Iowa Department of Natural Resources is about the water quality management of Iowa's rivers, streams and lakes.

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This monthly report from the Iowa Department of Natural Resources is about the water quality management of Iowa's rivers, streams and lakes.

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Although during much of its geologic history Iowa was part of an interior sea, today what we see on the land surface has been heavily influenced by recent glaciation. Everything from Iowa soils, rivers, lakes, and hills has been influenced by glaciation. Most of Iowa’s bedrock is hidden beneath a thick mantle of deposits from the Cenozoic (i.e., new life) Era, spanning the last 65 million years. Geologists have divided the Cenozoic Era into two periods. These are the Tertiary (1.8-65 million years ago) and Quaternary Periods (recent to 1.8 million years ago). Most geologic records in Iowa are from the Quaternary period, and include glacial till and loess.

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Want a glimpse at past vegetation? Studying pollen and other plant remains, which are preserved for example in lake sediments or mires for thousands of years, allows us to document regional occurrences of plant species over radiocarbon-dated time series. Such vegetation reconstructions derived from optical analyses of fossil samples are inherently incomplete because they only comprise taxa that contribute sufficient amounts of pollen, spores, macrofossil or other evidences. To complement optical analyses for paleoecological inference, molecular markers applied to ancient DNA (aDNA) may help in disclosing information hitherto inaccessible to biologists. Parducci etal. (2013) targeted aDNA from sediment cores of two lakes in the Scandes Mountains with generic primers in a meta-barcoding approach. When compared to palynological records from the same cores, respective taxon lists show remarkable differences in their compositions, but also in quantitative representation and in taxonomic resolution similar to a previous study (JOrgensen etal. 2012). While not free of assumptions that need critical and robust testing, notably the question of possible contamination, this study provides thrilling prospects to improve our knowledge about past vegetation composition, but also other organismic groups, stored as a biological treasure in the ground.

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BACKGROUND: The exceptionally diverse species flocks of cichlid fishes in East Africa are prime examples of parallel adaptive radiations. About 80% of East Africa's more than 1 800 endemic cichlid species, and all species of the flocks of Lakes Victoria and Malawi, belong to a particularly rapidly evolving lineage, the haplochromines. One characteristic feature of the haplochromines is their possession of egg-dummies on the males' anal fins. These egg-spots mimic real eggs and play an important role in the mating system of these maternal mouthbrooding fish. RESULTS: Here, we show that the egg-spots of haplochromines are made up of yellow pigment cells, xanthophores, and that a gene coding for a type III receptor tyrosine kinase, colony-stimulating factor 1 receptor a (csf1ra), is expressed in egg-spot tissue. Molecular evolutionary analyses reveal that the extracellular ligand-binding and receptor-interacting domain of csf1ra underwent adaptive sequence evolution in the ancestral lineage of the haplochromines, coinciding with the emergence of egg-dummies. We also find that csf1ra is expressed in the egg-dummies of a distantly related cichlid species, the ectodine cichlid Ophthalmotilapia ventralis, in which markings with similar functions evolved on the pelvic fin in convergence to those of the haplochromines. CONCLUSION: We conclude that modifications of existing signal transduction mechanisms might have evolved in the haplochromine lineage in association with the origination of anal fin egg-dummies. That positive selection has acted during the evolution of a color gene that seems to be involved in the morphogenesis of a sexually selected trait, the egg-dummies, highlights the importance of further investigations of the comparative genomic basis of the phenotypic diversification of cichlid fishes.

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PURPOSE: To characterize the clinical, psychophysical, and electrophysiological phenotypes in a five-generation Swiss family with dominantly inherited retinitis pigmentosa caused by a T494M mutation in the Precursor mRNA-Processing factor 3 (PRPF3) gene, and to relate the phenotype to the underlying genetic mutation. METHODS: Eleven affected patients were ascertained for phenotypic and genotypic characterization. Ophthalmologic evaluations included color vision testing, Goldmann perimetry, and digital fundus photography. Some patients had autofluorescence imaging, Optical Coherence Tomography, and ISCEV-standard full-field electroretinography. All affected patients had genetic testing. RESULTS: The age of onset of night blindness and the severity of the progression of the disease varied between members of the family. Some patients reported early onset of night blindness at age three, with subsequent severe deterioration of visual acuity, which was 0.4 in the best eye after their fifties. The second group of patients had a later onset of night blindness, in the mid-twenties, with a milder disease progression and a visual acuity of 0.8 at age 70. Fundus autofluorescence imaging and electrophysiological and visual field abnormalities also showed some degree of varying phenotypes. The autofluorescence imaging showed a large high-density ring bilaterally. Myopia (range: -0.75 to -8) was found in 10/11 affected subjects. Fundus findings showed areas of atrophy along the arcades. A T494M change was found in exon 11 of the PRPF3 gene. The change segregates with the disease in the family. CONCLUSIONS: A mutation in the PRPF3 gene is rare compared to other genes causing autosomal dominant retinitis pigmentosa (ADRP). Although a T494M change has been reported, the family in our study is the first with variable expressivity. Mutations in the PRPF3 gene can cause a variable ADRP phenotype, unlike in the previously described Danish, English, and Japanese families. Our report, based on one of the largest affected pedigree, provides a better understanding as to the phenotype/genotype description of ADRP caused by a PRPF3 mutation.

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A river can wander through the land in any way it pleases. People, however, face a few legal restrictions when following rivers, lakes, and streams through privately owned land. Care must be taken not to trespass on private property.

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Describe los resultados de la experiencia de pesca experimental empleando una red mini-granton modificada, empleando la red danesa (Danish Seine) y usando la Fyke Net (biturón), realizada en la Albúfera Medio Mundo.

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Els llacs i embassaments es comporten com oscil·ladors multi modals forçats pel vent. Els modes propers als de l'agent forçant són seleccionats d'entre tot l'espectre possible, com a modes d'oscil·lació de la massa d'aigua. En general els modes predominants són els modes baixos, és a dir els modes amb pocs nodes. Això passa especialment als llacs que es poden considerar formats per dues capes. No obstant, als embassaments mediterranis l'estratificació és quasi continua degut sobretot a l'extracció d'aigua i es poden aproximar per sistemes formats per moltes capes. En aquests casos l'espectre possible d'ones internes és fa molt més gran. Als embassaments de Sau i Béznar el vent té una periodicitat de 24 hores i força modes alts d'oscil·lació. Concretament, a l'embassament de Sau hi hem detectat modes amb 2 i 3 nodes verticals i 2 nodes horitzontals (V2H2 i V3H2) i a l'embassament de Béznar modes de fins a 5 nodes verticals i un node horitzontal (V5H1). Hem fet simulacions numèriques per veure l'estructura oscil·latòria en aquests modes de vibració

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Summary: The Merya - the great lakes people