513 research outputs found

    Nonlocal and local wind forcing dependence of the Atlantic meridional overturning circulation and its depth scale

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    We use wind sensitivity experiments to understand the wind forcing dependencies of the level of no motion and the e-folding pycnocline scale as well as their relationship to northward transport of the mid-depth Atlantic meridional overturning circulation (AMOC) south and north of the equator. In contrast to previous studies, we investigate the interplay of nonlocal and local wind effects on a decadal timescale. We use 30-year simulations with a high-resolution ocean general circulation model (OGCM) which is an eddy-resolving version of the Max Planck Institute Ocean Model (MPIOM). Our findings deviate from the common perspective that the AMOC is a nonlocal phenomenon only, because northward transport in the inter-hemispheric cell can only be understood by analyzing nonlocal Southern Ocean wind effects and local wind effects in the northern hemisphere downwelling region where Ekman pumping takes place. Southern Ocean wind forcing predominantly determines the magnitude of the pycnocline scale throughout the basin, whereas northern hemisphere winds additionally influence the level of no motion locally. In that respect, the level of no motion is a better proxy for northward transport and mid-depth velocity profiles despite the Ekman return flow which is found to be baroclinic. We compare our results inferred from the wind experiments and a 100-year global warming experiment in which the atmospheric CO2 concentration is quadrupled, using MPIOM coupled to an atmospheric model. We find that the evolution of the level of no motion in response to global warming represents changes in vertical velocity profiles or northward transport, whereas the changes of the pycnocline scale are opposite to the changes of the level of no motion over time. Using the level of no motion as depth scale, the analysis of the wind experiments and the warming experiment suggests a hemisphere-dependent scaling of the strength of AMOC. Furthermore, we put forward the idea that the ability of numerical models to capture the spatial and temporal variations of the level of no motion is crucial to reproduce the mid-depth cell in an appropriate wa

    Hypertrophic pyloric stenosis: tips and tricks for ultrasound diagnosis

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    We describe a systematic approach to the ultrasound (US) examination of the antropyloric region in children. US is the modality of choice for the diagnosis of hypertrophic pyloric stenosis (HPS). The imaging features of the normal pylorus and the diagnostic findings in HPS are reviewed and illustrated in this pictorial essay. Common difficulties in performing the examination and tips to help overcome them will also be discussed

    Protective effect of stromal Dickkopf-3 in prostate cancer: opposing roles for TGFBI and ECM-1

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    Aberrant transforming growth factor–β (TGF-β) signaling is a hallmark of the stromal microenvironment in cancer. Dickkopf-3 (Dkk-3), shown to inhibit TGF-β signaling, is downregulated in prostate cancer and upregulated in the stroma in benign prostatic hyperplasia, but the function of stromal Dkk-3 is unclear. Here we show that DKK3 silencing in WPMY-1 prostate stromal cells increases TGF-β signaling activity and that stromal cellconditioned media inhibit prostate cancer cell invasion in a Dkk-3-dependent manner. DKK3 silencing increased the level of the cell-adhesion regulator TGF-β–induced protein (TGFBI) in stromal and epithelial cell-conditioned media, and recombinant TGFBI increased prostate cancer cell invasion. Reduced expression of Dkk-3 in patient tumors was associated with increased expression of TGFBI. DKK3 silencing reduced the level of extracellular matrix protein-1 (ECM-1) in prostate stromal cell-conditioned media but increased it in epithelial cell-conditioned media, and recombinant ECM-1 inhibited TGFBI-induced prostate cancer cell invasion. Increased ECM1 and DKK3 mRNA expression in prostate tumors was associated with increased relapse-free survival. These observations are consistent with a model in which the loss of Dkk-3 in prostate cancer leads to increased secretion of TGFBI and ECM-1, which have tumor-promoting and tumor-protective roles, respectively. Determining how the balance between the opposing roles of extracellular factors influences prostate carcinogenesis will be key to developing therapies that target the tumor microenvironment

    Visual Network Analysis of Dynamic Metabolic Pathways

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    Abstract. We extend our previous work on the exploration of static metabolic networks to evolving, and therefore dynamic, pathways. We apply our visualization software to data from a simulation of early metabolism. Thereby, we show that our technique allows us to test and argue for or against different scenarios for the evolution of metabolic pathways. This supports a profound and efficient analysis of the structure and properties of the generated metabolic networks and its underlying components, while giving the user a vivid impression of the dynamics of the system. The analysis process is inspired by Ben Shneiderman’s mantra of information visualization. For the overview, user-defined diagrams give insight into topological changes of the graph as well as changes in the attribute set associated with the participating enzymes, substances and reactions. This way, “interesting features” in time as well as in space can be recognized. A linked view implementation enables the navigation into more detailed layers of perspective for in-depth analysis of individual network configuration

    Comparing online campaigning: The evolution of interactive campaigning from Royal to Obama to Hollande

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    © 2016 Macmillan Publishers Ltd.Studies of election campaigning from a comparative perspective have a long history; this study approaches the topic through a most-similar regime perspective to explore the ebb and flow of innovations in digital campaigning between presidential campaigns in France and the United States. The hype surrounding the 2008 Obama campaign overshadowed innovations in France the previous year, while the 2011 contest gained little serious academic attention. Using a well-established content analysis methodology the research explains the strategic design of the digital dimension of the campaigns of the leading candidates (Sarkozy and Royal in 2007, Obama and McCain in 2008, Hollande and Sarkozy in 2011, and Obama and Romney in 2012). The research then assesses the strategic contribution of each feature using schematics for understanding the flow of communication, as well as the strategy employed by each candidate. The key findings are that the campaigns are becoming more interactive, with the citizens increasingly more able to enter into conversations with the campaign teams, however interactivity when it happens is carefully controlled. Largely, however, there is a strong similarity masked by the sophistication of US contests. Despite the advances in communication technology and the social trends they have instigated, campaign communication remains top-down and digital technologies are used to gather data and push supporters towards activism than creating an inclusive space for the co-creation that cyberoptimists argued would revitalise the structures of democracy

    An Evaluation of Ballute Entry Systems for Lunar Return Missions

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    AIAA Atmospheric Flight Mechanics Conference August 2006, Keystone, CO.This study investigates the advantages and feasibility of using ballutes for Earth entry at lunar return velocities. Using analysis methods suitable for conceptual design and assuming a CEV type entry vehicle, multiple entry strategies were investigated. Entries that jettison the ballute after achieving low Earth orbit conditions were shown to reduce heating rates to within reusable thermal protection system limits. Deceleration was mitigated to approximately four g's when a moderate amount of lift was applied subsequent to ballute jettison. Primary ballute size drivers are the thermal limitations and areal densities of the ballute material. Performance requirements for both of those metrics were generated over a range of total ballute system masses. Lastly, preliminary investigation of a lower mass cargo variant of the CEV allowed for additional reduction of ballute system mass. However, ballute system mass as a percentage of the total entry mass was shown to be relatively independent of the entry mass

    Imaging of the urinary tract: the role of CT and MRI

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    Computed tomography (CT) and magnetic resonance imaging (MRI) are increasingly valuable tools for assessing the urinary tract in adults and children. However, their imaging capabilities, while overlapping in some respects, should be considered as complementary, as each technique offers specific advantages and disadvantages both in actual inherent qualities of the technique and in specific patients and with a specific diagnostic question. The use of CT and MRI should therefore be tailored to the patient and the clinical question. For the scope of this article, the advantages and disadvantages of these techniques in children will be considered; different considerations will apply in adult practice

    Duplication events downstream of IRX1 cause North Carolina macular dystrophy at the MCDR3 locus

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    Autosomal dominant North Carolina macular dystrophy (NCMD) is believed to represent a failure of macular development. The disorder has been linked to two loci, MCDR1 (chromosome 6q16) and MCDR3 (chromosome 5p15-p13). Recently, non-coding variants upstream of PRDM13 (MCDR1) and a duplication including IRX1 (MCDR3) have been identified. However, the underlying disease-causing mechanism remains uncertain. Through a combination of sequencing studies on eighteen NCMD families, we report two novel overlapping duplications at the MCDR3 locus, in a gene desert downstream of IRX1 and upstream of ADAMTS16. One duplication of 43 kb was identified in nine families (with evidence for a shared ancestral haplotype), and another one of 45 kb was found in a single family. Three families carry the previously reported V2 variant (MCDR1), while five remain unsolved. The MCDR3 locus is thus refined to a shared region of 39 kb that contains DNAse hypersensitive sites active at a restricted time window during retinal development. Publicly available data confirmed expression of IRX1 and ADAMTS16 in human fetal retina, with IRX1 preferentially expressed in fetal macula. These findings represent a major advance in our understanding of the molecular genetics of NCMD and provide insights into the genetic pathways involved in human macular development

    The common ABCA4 variant p.Asn1868ile shows nonpenetrance and variable expression of stargardt disease when present in trans with severe variants

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    PURPOSE. To assess the occurrence and the disease expression of the common p.Asn1868Ile variant in patients with Stargardt disease (STGD1) harboring known, monoallelic causal ABCA4 variants. METHODS. The coding and noncoding regions of ABCA4 were sequenced in 67 and 63 STGD1 probands respectively, harboring monoallelic ABCA4 variants. In case p.Asn1868Ile was detected, segregation analysis was performed whenever possible. Probands and affected siblings harboring p.Asn1868Ile without additional variants in cis were clinically evaluated retrospe

    Combining Computational Prediction of Cis-Regulatory Elements with a New Enhancer Assay to Efficiently Label Neuronal Structures in the Medaka Fish

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    The developing vertebrate nervous system contains a remarkable array of neural cells organized into complex, evolutionarily conserved structures. The labeling of living cells in these structures is key for the understanding of brain development and function, yet the generation of stable lines expressing reporter genes in specific spatio-temporal patterns remains a limiting step. In this study we present a fast and reliable pipeline to efficiently generate a set of stable lines expressing a reporter gene in multiple neuronal structures in the developing nervous system in medaka. The pipeline combines both the accurate computational genome-wide prediction of neuronal specific cis-regulatory modules (CRMs) and a newly developed experimental setup to rapidly obtain transgenic lines in a cost-effective and highly reproducible manner. 95% of the CRMs tested in our experimental setup show enhancer activity in various and numerous neuronal structures belonging to all major brain subdivisions. This pipeline represents a significant step towards the dissection of embryonic neuronal development in vertebrates
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