992 resultados para Yangtze River Delta


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This study is a concise summary of a study of trail users on the Raccoon River Valley Trail commissioned by the Dallas County Conservation Board. It provides information associated with natural and cultural resources.

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Skin morphogenesis, maintenance, and healing after wounding require complex epithelial-mesenchymal interactions. In this study, we show that for skin homeostasis, interleukin-1 (IL-1) produced by keratinocytes activates peroxisome proliferator-activated receptor beta/delta (PPARbeta/delta) expression in underlying fibroblasts, which in turn inhibits the mitotic activity of keratinocytes via inhibition of the IL-1 signaling pathway. In fact, PPARbeta/delta stimulates production of the secreted IL-1 receptor antagonist, which leads to an autocrine decrease in IL-1 signaling pathways and consequently decreases production of secreted mitogenic factors by the fibroblasts. This fibroblast PPARbeta/delta regulation of the IL-1 signaling is required for proper wound healing and can regulate tumor as well as normal human keratinocyte cell proliferation. Together, these findings provide evidence for a novel homeostatic control of keratinocyte proliferation and differentiation mediated via PPARbeta/delta regulation in dermal fibroblasts of IL-1 signaling. Given the ubiquitous expression of PPARbeta/delta, other epithelial-mesenchymal interactions may also be regulated in a similar manner.

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The 2011 Missouri River flooding caused significant damage to many geo-infrastructure systems including levees, bridge abutments/foundations, paved and unpaved roadways, culverts, and embankment slopes in western Iowa. The flooding resulted in closures of several interchanges along Interstate 29 and of more than 100 miles of secondary roads in western Iowa, causing severe inconvenience to residents and losses to local businesses. The main goals of this research project were to assist county and city engineers by deploying and using advanced technologies to rapidly assess the damage to geo-infrastructure and develop effective repair and mitigation strategies and solutions for use during future flood events in Iowa. The research team visited selected sites in western Iowa to conduct field reconnaissance, in situ testing on bridge abutment backfills that were affected by floods, flooded and non-flooded secondary roadways, and culverts. In situ testing was conducted shortly after the flood waters receded, and several months after flooding to evaluate recovery and performance. Tests included falling weight deflectometer, dynamic cone penetrometer, three-dimensional (3D) laser scanning, ground penetrating radar, and hand auger soil sampling. Field results indicated significant differences in roadway support characteristics between flooded and non-flooded areas. Support characteristics in some flooded areas recovered over time, while others did not. Voids were detected in culvert and bridge abutment backfill materials shortly after flooding and several months after flooding. A catalog of field assessment techniques and 20 potential repair/mitigation solutions are provided in this report. A flow chart relating the damages observed, assessment techniques, and potential repair/mitigation solutions is provided. These options are discussed for paved/unpaved roads, culverts, and bridge abutments, and are applicable for both primary and secondary roadways.

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As a result of the GUADALMED project, undertaken in Iberian Mediterranean basins, to which were added samples taken by the junior author in the area, we collected numerous caddisfly larvae, pupae and adults. Some larvae were also reared in the lab to obtain adults and allow proper identification. A total of 90 species were identified, which accounts for more than a fourth of the species known in the Iberian Peninsula and Balearic Islands. Here we confirm the presence of doubtful species in the Iberian Peninsula (Glyphotaelius pellucidus) and we expand the distribution range of others (Lype reducta, Micrasema minimum, Limnephilus guadarramicus, Sericostoma pyrenaicum). Moreover, because of the unconformity of morphological larval characteristics with present taxonomical keys (Mesophylax aspersus) or lack of larvae descriptions (Allogamus mortoni, Stenophylax espanioli), here we include some relevant taxonomical aspects that are useful to identify larvae. A brief description of the larva of a possible new species of Hydropsyche (from now on H. gr. instabilis) is also given. Los tricópteros (Insecta) recolectados en las cuencas mediterráneas de la Península Ibérica: notas taxonómicas y requerimientos ecológicos Como resultado de los estudios realizados en el proyecto GUADALMED en las cuencas de los ríos mediterráneos peninsulares y otros muestreos realizados por la primera autora del trabajo se han recolectado numerosas larvas, pupas y adultos de tricópteros. Algunas larvas fueron criadas en el laboratorio para la obtención de adultos y con ello asegurar su identificación. Se han identificado un total de 90 especies que suponen más de una cuarta parte de las especies actualmente conocidas en la Península Ibérica y Baleares. En este trabajo se confirma la presencia, hasta ahora dudosa en la Península Ibérica, de algunas especies (Glyphotaelius pellucidus) y se amplia el área de distribución de otras (Lype reducta, Micrasema minimum, Limnephilus guadarramicus, Sericostoma pyrenaicum). Además, se incluyen algunos aspectos taxonómicos relevantes para la identificación de algunas larvas en futuros estudios, debido a que las claves ya existentes no describen correctamente la larva (Mesophylax aspersus) o porque se trata de larvas sin describir (Allogamus mortoni, Stenophylax espanioli). Se añade también una somera descripción de la larva de una posible nueva especie de Hydropsyche (citada aquí como H. gr. instabilis) y que requiere un estudio más detallado.

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T cells expressing T cell receptor (TCR) complexes that lack CD3 delta, either due to deletion of the CD3 delta gene, or by replacement of the connecting peptide of the TCR alpha chain, exhibit severely impaired positive selection and TCR-mediated activation of CD8 single-positive T cells. Because the same defects have been observed in mice expressing no CD8 beta or tailless CD8 beta, we examined whether CD3 delta serves to couple TCR.CD3 with CD8. To this end we used T cell hybridomas and transgenic mice expressing the T1 TCR, which recognizes a photoreactive derivative of the PbCS 252-260 peptide in the context of H-2K(d). We report that, in thymocytes and hybridomas expressing the T1 TCR.CD3 complex, CD8 alpha beta associates with the TCR. This association was not observed on T1 hybridomas expressing only CD8 alpha alpha or a CD3 delta(-) variant of the T1 TCR. CD3 delta was selectively co-immunoprecipitated with anti-CD8 antibodies, indicating an avid association of CD8 with CD3 delta. Because CD8 alpha beta is a raft constituent, due to this association a fraction of TCR.CD3 is raft-associated. Cross-linking of these TCR-CD8 adducts results in extensive TCR aggregate formation and intracellular calcium mobilization. Thus, CD3 delta couples TCR.CD3 with raft-associated CD8, which is required for effective activation and positive selection of CD8(+) T cells.

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Degradation of unsaturated fatty acids through the peroxisomal beta-oxidation pathway requires the participation of auxiliary enzymes in addition to the enzymes of the core beta-oxidation cycle. The auxiliary enzyme delta(3,5),delta(2,4)-dienoyl-coenzyme A (CoA) isomerase has been well studied in yeast (Saccharomyces cerevisiae) and mammals, but no plant homolog had been identified and characterized at the biochemical or molecular level. A candidate gene (At5g43280) was identified in Arabidopsis (Arabidopsis thaliana) encoding a protein showing homology to the rat (Rattus norvegicus) delta(3,5),delta(2,4)-dienoyl-CoA isomerase, and possessing an enoyl-CoA hydratase/isomerase fingerprint as well as aspartic and glutamic residues shown to be important for catalytic activity of the mammalian enzyme. The protein, named AtDCI1, contains a peroxisome targeting sequence at the C terminus, and fusion of a fluorescent protein to AtDCI1 directed the chimeric protein to the peroxisome in onion (Allium cepa) cells. AtDCI1 expressed in Escherichia coli was shown to have delta(3,5),delta(2,4)-dienoyl-CoA isomerase activity in vitro. Furthermore, using the synthesis of polyhydroxyalkanoate in yeast peroxisomes as an analytical tool to study the beta-oxidation cycle, expression of AtDCI1 was shown to complement the yeast mutant deficient in the delta(3,5),delta(2,4)-dienoyl-CoA isomerase, thus showing that AtDCI1 is also appropriately targeted to the peroxisome in yeast and has delta(3,5),delta(2,4)-dienoyl-CoA isomerase activity in vivo. The AtDCI1 gene is expressed constitutively in several tissues, but expression is particularly induced during seed germination. Proteins showing high homology with AtDCI1 are found in gymnosperms as well as angiosperms belonging to the Monocotyledon or Dicotyledon classes.

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El análisis sísmico de perfiles de alta resolución del tipo ((uniboom)), realizados en la plataforma interna al N del Delta del Ebro, permite definir las unidades sísmicas y establecer la estructura sedimentaria del recubrimiento cuaternario medio/superior. Ambos aspectos reflejan la influencia diferencial de los procesos dinámicos y de las oscilaciones eustáticas.

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The diverse vertebrate remains from the Upper Cretaceous freshwater settings at Iharkut, Hungary, contain two fossil groups, Pycnodontiformes fish and Mosasauridae that are almost exclusively known from marine palaeo-environments. Hence, their appearance in alluvial sediments is very unusual. Trace element and isotope compositions of the remains have been analyzed to investigate the taphonomy and the ecological differences among the different fossil groups present at Iharkut. All examined fossils have undergone post-depositional diagenetic alteration, which resulted in high concentrations of REE, U, and Fe, together with almost complete homogenization of delta(18)O(CO3) values. Similar REE patterns in different fossils suggest a common origin for all remains, hence the discovered species most likely lived in the same local ecosystem. Despite partial diagenetic overprinting, the delta(18)O(PO4) values of the fossils indicate sufficient taxon-specific isotopic diversity to permit some broad conclusions on the palaeo-environment of the fossils. In particular, it is apparent that the isotopic composition of the Pycnodontiformes fish and Mosasauridae remains is most compatible with a freshwater palaeo-habitat and incompatible with a marine palaeo-environment. In addition, the Sr concentration and isotope data indicate that the Pycnodontiformes and Mosasauridae likely lived predominantly in a freshwater environment and were not simply occasional visitors to the Iharkut river ecosystem. Regarding other fossil groups, high delta(18)O(PO4) values of Alligatoroidea and Iharkutosuchus teeth suggest that these small crocodile species might have inhabited swamps and ponds where the water was relatively rich in (18)O due to evaporation. (c) 2009 Elsevier B.V. All rights reserved.

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Isotopic analyses on bulk carbonates are considered a useful tool for palaeoclimatic reconstruction assuming calcite precipitation occurring at oxygen isotope equilibrium with local water and detrital carbonate input being absent or insignificant. We present results from Lake Neuchatel (western Switzerland) that demonstrate equilibrium precipitation of calcite, except during high productivity periods, and the presence of detrital and resuspended calcite. Mineralogy, geochemistry and stable isotope values of Lake Neuchatel trap sediments and adjacent rivers suspension were studied. Mineralogy of suspended matter in the major inflowing rivers documents an important contribution of detrital carbonates, predominantly calcite with minor amounts of dolomite and ankerite. Using mineralogical data, the quantity of allochthonous calcite can be estimated by comparing the ratio ankerite + dolomite/calcite + ankerite + dolomite in the inflowing rivers and in the traps. Material taken from sediment traps shows an evolution from practically pure endogenic calcite in summer (10-20% detrital material) to higher percentages of detrital material in winter (up to 20-40%). Reflecting these mineralogical variations, delta(13)C and delta(18)O values of calcite from sediment traps are more negative in summer than in winter times. Since no significant variations in isotopic composition of lake water were detected over one year, factors controlling oxygen isotopic composition of calcite in sediment traps are the precipitation temperature, and the percentage of resuspended and detrital calcite. Samples taken close to the river inflow generally have higher delta values than the others, confirming detrital influence. SEM and isotopic studies on different size fractions (<2, 2-6, 6-20, 20-60, >60 mu m) of winter and summer samples allowed the recognition of resuspension and to separate new endogenic calcite from detrital calcite. Fractions >60 and (2 mu m have the highest percentage of detritus, Fractions 2-6 and 6-20 mu m are typical for the new endogenic calcite in summer, as given by calculations assuming isotopic equilibrium with local water. In winter such fractions show similar values than in summer, indicating resuspension. Using the isotopic composition of sediment traps material and of different size fractions, as well as the isotopic composition of lake water, the water temperature measurements and mineralogy, we re-evaluated the bulk carbonate potential for palaeoclimatic reconstruction in the presence of detrital and re-suspended calcite. This re-evaluation leads to the following conclusion: (1) the endogenic signal can be amplified by applying a particle-size separation, once the size of endogenic calcite is known from SEM study; (2) resuspended calcite does not alter the endogenic signal, but it lowers the time resolution; (3) detrital input decreases at increasing distances from the source, and it modifies the isotopic signal only when very abundant; (4) influence of detrital calcite on bulk sediment isotopic composition can be calculated. (C) 1998 Elsevier Science B.V. All rights reserved.

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This report from the University Hygienic Laboratory contains the results of a chlordane study of the Cedar River taken in the spring and summer of 1985 after it was discovered from a routine fish tissue monitoring program in Iowa that it contained levels of chlordane in excess of the FDA action level.

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Research has found that both flood magnitude and frequency in the UK may have increased over the last five decades. However, evaluating whether or not this is a systematic trend is difficult because of the lack of longer records. Here we compile and consider an extreme flood record that extends back to 1770. Since 1770, there have been 137 recorded extreme floods. However, over this period, there is not a unidirectional trend of rising extreme flood risk over time. Instead, there are clear flood-rich and flood-poor periods. Three main flood-rich periods were identified: 18731904, 19231933, and 1994 onwards. To provide a first analysis of what is driving these periods, and given the paucity of more sophisticated datasets that extend back to the 18th century, objective Lamb weather types were used. Of the 27 objective Lamb weather types, only 11 could be associated with the extreme floods during the gauged period, and only 5 of these accounted for > 80% of recorded extreme floods The importance of these five weather types over a longer timescale for flood risk in Carlisle was assessed, through calculating the proportion of each hydrological year classified as being associated with these flood-generating weather types. Two periods clearly had more than the average proportions of the year classified as one of the flood causing weather types; 19001940 and 19832007; and these two periods both contained flood-rich hydrological records. Thus, the analysis suggests that systematic organisation of the North Atlantic climate system may be manifest as periods of elevated and reduced flood risk, an observation that has major implications for analyses that assume that climatic drivers of flood risk can be either statistically stationary or are following a simple trend. Copyright (c) 2011 Royal Meteorological Society

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This is a story about a highway project near the small town of Wever, Iowa, and an American Indian village that existed at the location prior to the Europeans' arrival. The culture that lived in this village existed in a 10 state region of the Upper Midwest and may have been the ancestors of tribes living in the Midwest when European explorers entered the region. An archaeological recovery of information from the site was undertaken by the Iowa Department of Transportation because four-lane construction of U.S. 61 could not be accomplished without destroying most of the site. This site proved to be one of the richest archaeological finds in the State of Iowa. ǂc Iowa Department of Transportation.

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Flood-plain and channel-aggradation rates were estimated at selected bridge sites in central and eastern Iowa using four aggradation-measurement methods. Aggradation rates were quantified at 10 bridge sites on the Iowa River upstream of Coralville Lake and at two bridge sites in the central part of Skunk River Basin. Measurement periods used to estimate average aggradation rates ranged in length from 1 to 98 years and varied among methods and sites. A direct comparison cannot be made between aggradation rates calculated using each of the four measurement methods because of differences in time periods and aggradational processes that were measured by each method.

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We describe the development based on 454 pyrosequencing technology of thirteen microsatellite markers for two closely related species of lamprey: Lampetra fluviatilis and L. planeri. The number of alleles per locus ranged from 2 to 5 in L. fluviatilis and from 2 to 6 in L. planeri. Gene diversity ranged from 0.062 to 0.718 in L. fluviatilis and from 0.322 to 0.677 in L. planeri. These markers will be helpful to study population genetic structure of both species and resolve their taxonomic status as separate species or ecotypes of a single species.

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peroxisome proliferator-activated receptors (PPARs) are nuclear receptors acting as lipid sensors. Besides its metabolic activity in peripheral organs, the PPAR beta/delta isotype is highly expressed in the brain and its deletion in mice induces a brain developmental defect. Nevertheless, exploration of PPARbeta action in the central nervous system remains sketchy. The lipid content alteration observed in PPARbeta null brains and the positive action of PPARbeta agonists on oligodendrocyte differentiation, a process characterized by lipid accumulation, suggest that PPARbeta acts on the fatty acids and/or cholesterol metabolisms in the brain. PPARbeta could also regulate central inflammation and antioxidant mechanisms in the damaged brain. Even if not fully understood, the neuroprotective effect of PPARbeta agonists highlights their potential benefit to treat various acute or chronic neurological disorders. In this perspective, we need to better understand the basic function of PPARbeta in the brain. This review proposes different leads for future researches.