451 research outputs found
Stable isotope characterization of pedogenic and lacustrine carbonates from the Chinese Tian Shan: constraints on the Mesozoic - Lower Cenozoic palaeo-environmental evolution
International audienceIn the MesozoicâCenozoic continental deposits of the Tian Shan area, two main levels containing pedogenic carbonates have been identified on both the southern and northern foothills of the range: one in the Upper Jurassic series and one in the Upper CretaceousâLower Palaeocene series. In order to reconstruct the palaeoenvironmental and palaeotopographic characteristics of the Tian Shan area during these two periods, we measured the oxygen and carbon isotope composition of these pedogenic carbonates (calcrete and nodules). The stable isotope compositions are homogeneous: most ÎŽ18O values are between 21 and 25â° and most ÎŽ13C values are between â4 and â6â°. No distinction can be made between the calcrete and nodule isotopic compositions. The constancy of isotopic values across the Tian Shan is evidence of a development of these calcification features in similar palaeoenvironmental conditions. The main inference is that no significant relief existed in that area at the CretaceousâPalaeogene boundary, implying that most of the present relief developed later, during the Cenozoic. In addition to the pedogenic carbonates, few beds of limestones interstratified in the Jurassic series of the southern foothills display oxygen and carbon isotope compositions typical of lacustrine carbonates, ruling out brackish water incursion at that period in the regio
Going to the exclusive show : exhibition strategies and moviegoing memories of Disneys animated feature films in Ghent (1937-1982)
This is a case study of the exploitation and experience of Disney's animated feature films from the 1930s to the 1980s in Ghent (Belgium). It is a historical study of programming practices and financial strategies which constructed childhood memories on watching Disney. The study is a contribution to a historical understanding of the implications of global distribution of film as cultural products and the counter pull of localism. Using a multi-method approach, the argument is made that the scarce screenings were strategically programmed to uplift the moviegoing experience into something out of the ordinary in everyday life. Programming and revenue data characterize the screenings as exclusive and generating high intakes. Consequently, the remembered screenings did not exhale an easy accessible social status nor an image of pervasiveness of popular childhood film, contradictory to conventional accounts of Disney's ubiquity in popular culture
Reconnaissance Basement Geology and Tectonics of South Zealandia
We report new UâPb zircon ages, geochemical and isotopic data for Mesozoic igneous rocks, and new seismic interpretations of mostly submerged South Zealandia (1.5 Mkm2). We use these data, along with existing geological and geophysical data sets, to refine the extent and nature of geological units. Our new 1:25 M geological map of South Zealandia provides a regional framework to investigate the rifting and breakup that formed Zealandia, Earth's most submerged continent. Samples of prerift (preâ100 Ma) plutonic rocks can be matched with onâland New Zealand igneous suites and indicate an eastâwest strike for the subductionârelated 260 to 105âMa Median Batholith across the Campbell Plateau. The plutonic chronology of formerly contiguous plutonic rocks in West Antarctica reveals similar pulses and lulls to the Median Batholith. Contrary to previous interpretations, the Median Batholith does not coincide with the 1,600âkmâlong Campbell Magnetic Anomaly System. Instead we interpret the continental magnetic anomalies to represent a mainly mafic igneous unit, whose shape and extent is controlled by synrift structures related to Gondwana breakup. Correlatives of some of these unsampled igneous rocks may be exposed as circa 85 Ma alkalic volcanic rocks on the Chatham Islands. Extension directions varied by up to 65° from 100 to 80 Ma, and we suggest this allowed this large area to thin considerably before final rupture to form new oceanic crust. Synrift (90â80 Ma) structures cut the oroclinal bend in southern South Island and support a preâearly Late Cretaceous age of orocline formation.The work was supported by Core Research Funding to GNS Science by the New Zealand Government Ministry of Business, Employment and Innovation
Uniform grain-size distribution in the active layer of a shallow, gravel-bedded, braided river (the Urumqi River, China) and implications for paleo-hydrology
The
grain-size distribution of ancient alluvial systems is commonly determined
from surface samples of vertically exposed sections of gravel deposits. This
method relies on the hypothesis that the grain-size distribution obtained
from a vertical cross section is equivalent to that of the riverbed. Such an
hypothesis implies first that the sediments are uniform in size in the river
bed, and second that the sampling method implemented on a vertical section
leads to a grain-size distribution equivalent to the bulk one. Here, we
report a field test of this hypothesis on granulometric samples collected in
an active, gravel-bedded, braided stream: the Urumqi River in China. We
compare data from volumetric samples of a trench excavated in an active
thread and from surface counts performed on the trench vertical faces. Based
on this data set, we show that the grain-size distributions obtained from all
the samples are similar and that the deposit is uniform at the scale of the
river active layer, a layer extending from the surface to a depth of
approximately 10Â times the size of the largest clasts. As a consequence, the
grid-by-number method implemented vertically leads to a grain-size
distribution equivalent to the one obtained by a bulk volumetric sampling.
This study thus brings support to the hypothesis that vertical surface counts
provide an accurate characterization of the grain-size distribution of
paleo-braided rivers.</p
A BAYESIAN GRAPHICAL MODELING APPROACH TO MICRORNA REGULATORY NETWORK INFERENCE
It has been estimated that about 30% of the genes in the human genome are
regulated by microRNAs (miRNAs). These are short RNA sequences that can
down-regulate the levels of mRNAs or proteins in animals and plants. Genes
regulated by miRNAs are called targets. Typically, methods for target
prediction are based solely on sequence data and on the structure information.
In this paper we propose a Bayesian graphical modeling approach that infers the
miRNA regulatory network by integrating expression levels of miRNAs with their
potential mRNA targets and, via the prior probability model, with their
sequence/structure information. We use a directed graphical model with a
particular structure adapted to our data based on biological considerations. We
then achieve network inference using stochastic search methods for variable
selection that allow us to explore the huge model space via MCMC. A
time-dependent coefficients model is also implemented. We consider experimental
data from a study on a very well-known developmental toxicant causing neural
tube defects, hyperthermia. Some of the pairs of target gene and miRNA we
identify seem very plausible and warrant future investigation. Our proposed
method is general and can be easily applied to other types of network inference
by integrating multiple data sources.Comment: Published in at http://dx.doi.org/10.1214/10-AOAS360 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Consensus Pathways Implicated in Prognosis of Colorectal Cancer Identified Through Systematic Enrichment Analysis of Gene Expression Profiling Studies
Background: A large number of gene expression profiling (GEP) studies on prognosis of colorectal cancer (CRC) has been performed, but no reliable gene signature for prediction of CRC prognosis has been found. Bioinformatic enrichment tools are a powerful approach to identify biological processes in high-throughput data analysis. Principal Findings: We have for the first time collected the results from the 23 so far published independent GEP studies on CRC prognosis. In these 23 studies, 1475 unique, mapped genes were identified, from which 124 (8.4%) were reported in at least two studies, with 54 of them showing consisting direction in expression change between the single studies. Using these data, we attempted to overcome the lack of reproducibility observed in the genes reported in individual GEP studies by carrying out a pathway-based enrichment analysis. We used up to ten tools for overrepresentation analysis of Gene Ontology (GO) categories or Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways in each of the three gene lists (1475, 124 and 54 genes). This strategy, based on testing multiple tools, allowed us to identify the oxidative phosphorylation chain and the extracellular matrix receptor interaction categories, as well as a general category related to cell proliferation and apoptosis, as the only significantly and consistently overrepresented pathways in the three gene lists, which were reported by several enrichment tools. Conclusions: Our pathway-based enrichment analysis of 23 independent gene expression profiling studies on prognosis of CRC identified significantly and consistently overrepresented prognostic categories for CRC. These overrepresented categories have been functionally clearly related with cancer progression, and deserve further investigation
Role of RhoA and rho kinase in lysophosphatidic acid-induced endothelial barrier dysfunction.
The online version of this article, along with updated information and services, is located on th
- âŠ