91 research outputs found

    An Investigation Of The Comparative Accuracy And Bias Of Equity Securities Analysts East And West European Firms Earnings Forecasts

    Get PDF
    This research investigates the comparative accuracy and bias of West European and East European firms equity securities analysts earnings forecasts for 29 European countries 12 of which are characterized as being East European.  We utilize measures of equity securities analysts earnings forecast accuracy and bias in making comparisons of the statistical properties of earnings forecasts for firms having domiciles in East European and West European countries.  Our results indicate that securities analysts earnings forecasts for companies domiciled with East European countries display larger forecast error and greater degree of optimistic forecast bias.  Our results persist after controlling for cross-listing of ADRs on US securities exchanges. We generalize our results using the growing literature on the ever-changing characteristics of the Russian people, Russian business professionals and the rapidly evolving Russian stock market and the transitional Russian political economy

    Impact of eV-mass sterile neutrinos on neutrino-driven supernova outflows

    Full text link
    Motivated by recent hints for sterile neutrinos from the reactor anomaly, we study active-sterile conversions in a three-flavor scenario (2 active + 1 sterile families) for three different representative times during the neutrino-cooling evolution of the proto-neutron star born in an electron-capture supernova. In our "early model" (0.5 s post bounce), the nu_e-nu_s MSW effect driven by Delta m^2=2.35 eV^2 is dominated by ordinary matter and leads to a complete nu_e-nu_s swap with little or no trace of collective flavor oscillations. In our "intermediate" (2.9 s p.b.) and "late models" (6.5 s p.b.), neutrinos themselves significantly modify the nu_e-nu_s matter effect, and, in particular in the late model, nu-nu refraction strongly reduces the matter effect, largely suppressing the overall nu_e-nu_s MSW conversion. This phenomenon has not been reported in previous studies of active-sterile supernova neutrino oscillations. We always include the feedback effect on the electron fraction Y_e due to neutrino oscillations. In all examples, Y_e is reduced and therefore the presence of sterile neutrinos can affect the conditions for heavy-element formation in the supernova ejecta, even if probably not enabling the r-process in the investigated outflows of an electron-capture supernova. The impact of neutrino-neutrino refraction is strong but complicated, leaving open the possibility that with a more complete treatment, or for other supernova models, active-sterile neutrino oscillations could generate conditions suitable for the r-process.Comment: 23 pages, including 14 figures and 2 tables (minor changes in the text). Matches published version in JCA

    E-government adoption: A cultural comparison

    Get PDF
    This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ Springer Science + Business Media, LLC 2008.E-government diffusion is an international phenomenon. This study compares e-government adoption in the U.K. to adoption in the U.S. In particular, this study seeks to determine if the same factors are salient in both countries. Several studies have explored citizen acceptance of e-government services in the U.S. However, few studies have explored this phenomenon in the U.K. To identify the similarities and differences between the U.K. and the U.S. a survey is conducted in the U.K. and the findings are compared to the literature that investigates diffusion in the U.S. This study proposes a model of e-government adoption in the U.K. based on salient factors in the U.S. A survey is administered to 260 citizens in London to assess the importance of relative advantage, trust and the digital divide on intention to use e-government. The results of binary logistic regression indicate that there are cultural differences in e-government adoption in the U.K. and the U.S. The results indicate that of the prevailing adoption constructs, relative advantage and trust are pertinent in both the U.S. and the U.K., while ICT adoption barriers such as access and skill may vary by culture. Implications for research and practice are discussed

    Electron Tomography of Fusiform Vesicles and Their Organization in Urothelial Cells

    Get PDF
    The formation of fusiform vesicles (FVs) is one of the most distinctive features in the urothelium of the urinary bladder. FVs represent compartments for intracellular transport of urothelial plaques, which modulate the surface area of the superficial urothelial (umbrella) cells during the distension-contraction cycle. We have analysed the three-dimensional (3D) structure of FVs and their organization in umbrella cells of mouse urinary bladders. Compared to chemical fixation, high pressure freezing gave a new insight into the ultrastructure of urothelial cells. Electron tomography on serial sections revealed that mature FVs had a shape of flattened discs, with a diameter of up to 1.2 µm. The lumen between the two opposing asymmetrically thickened membranes was very narrow, ranging from 5 nm to 10 nm. Freeze-fracturing and immunolabelling confirmed that FVs contain two opposing urothelial plaques connected by a hinge region that made an omega shaped curvature. In the central cytoplasm, 4–15 FVs were often organized into stacks. In the subapical cytoplasm, FVs were mainly organized as individual vesicles. Distension-contraction cycles did not affect the shape of mature FVs; however, their orientation changed from parallel in distended to perpendicular in contracted bladder with respect to the apical plasma membrane. In the intermediate cells, shorter and more dilated immature FVs were present. The salient outcome from this research is the first comprehensive, high resolution 3D view of the ultrastructure of FVs and how they are organized differently depending on their location in the cytoplasm of umbrella cells. The shape of mature FVs and their organization into tightly packed stacks makes them a perfect storage compartment, which transports large amounts of urothelial plaques while occupying a small volume of umbrella cell cytoplasm

    CUL-2<sup>LRR-1</sup> and UBXN-3 drive replisome disassembly during DNA replication termination and mitosis

    Get PDF
    Replisome disassembly is the final step of DNA replication in eukaryotes, involving the ubiquitylation and CDC48-dependent dissolution of the CMG helicase (CDC45-MCM-GINS). Using Caenorhabditis elegans early embryos and Xenopus laevis egg extracts, we show that the E3 ligase CUL-2(LRR-1) associates with the replisome and drives ubiquitylation and disassembly of CMG, together with the CDC-48 cofactors UFD-1 and NPL-4. Removal of CMG from chromatin in frog egg extracts requires CUL2 neddylation, and our data identify chromatin recruitment of CUL2(LRR1) as a key regulated step during DNA replication termination. Interestingly, however, CMG persists on chromatin until prophase in worms that lack CUL-2(LRR-1), but is then removed by a mitotic pathway that requires the CDC-48 cofactor UBXN-3, orthologous to the human tumour suppressor FAF1. Partial inactivation of lrr-1 and ubxn-3 leads to synthetic lethality, suggesting future approaches by which a deeper understanding of CMG disassembly in metazoa could be exploited therapeutically

    Lack of Cul4b, an E3 Ubiquitin Ligase Component, Leads to Embryonic Lethality and Abnormal Placental Development

    Get PDF
    Cullin-RING ligases (CRLs) complexes participate in the regulation of diverse cellular processes, including cell cycle progression, transcription, signal transduction and development. Serving as the scaffold protein, cullins are crucial for the assembly of ligase complexes, which recognize and target various substrates for proteosomal degradation. Mutations in human CUL4B, one of the eight members in cullin family, are one of the major causes of X-linked mental retardation. We here report the generation and characterization of Cul4b knockout mice, in which exons 3 to 5 were deleted. In contrast to the survival to adulthood of human hemizygous males with CUL4B null mutation, Cul4b null mouse embryos show severe developmental arrest and usually die before embryonic day 9.5 (E9.5). Accumulation of cyclin E, a CRL (CUL4B) substrate, was observed in Cul4b null embryos. Cul4b heterozygotes were recovered at a reduced ratio and exhibited a severe developmental delay. The placentas in Cul4b heterozygotes were disorganized and were impaired in vascularization, which may contribute to the developmental delay. As in human CUL4B heterozygotes, Cul4b null cells were selected against in Cul4b heterozygotes, leading to various degrees of skewed X-inactivation in different tissues. Together, our results showed that CUL4B is indispensable for embryonic development in the mouse

    NEDDylation is essential for Kaposi's sarcoma-associated herpesvirus latency and lytic reactivation and represents a novel anti-KSHV target.

    Get PDF
    Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of Kaposi's sarcoma (KS) and primary effusion lymphoma (PEL), which are aggressive malignancies associated with immunocompromised patients. For many non-viral malignancies, therapeutically targeting the ubiquitin proteasome system (UPS) has been successful. Likewise, laboratory studies have demonstrated that inhibition of the UPS might provide a promising avenue for the treatment of KSHV-associated diseases. The largest class of E3 ubiquitin ligases are the cullin-RING ligases (CRLs) that are activated by an additional ubiquitin-like protein, NEDD8. We show that pharmacological inhibition of NEDDylation (using the small molecule inhibitor MLN4924) is cytotoxic to PEL cells by inhibiting NF-κB. We also show that CRL4B is a novel regulator of latency as its inhibition reactivated lytic gene expression. Furthermore, we uncovered a requirement for NEDDylation during the reactivation of the KSHV lytic cycle. Intriguingly, inhibition prevented viral DNA replication but not lytic cycle-associated gene expression, highlighting a novel mechanism that uncouples these two features of KSHV biology. Mechanistically, we show that MLN4924 treatment precluded the recruitment of the viral pre-replication complex to the origin of lytic DNA replication (OriLyt). These new findings have revealed novel mechanisms that regulate KSHV latency and reactivation. Moreover, they demonstrate that inhibition of NEDDylation represents a novel approach for the treatment of KSHV-associated malignancies

    Urothelial Plaque Formation in Post-Golgi Compartments

    Get PDF
    Urothelial plaques are specialized membrane domains in urothelial superficial (umbrella) cells, composed of highly ordered uroplakin particles. We investigated membrane compartments involved in the formation of urothelial plaques in mouse umbrella cells. The Golgi apparatus did not contain uroplakins organized into plaques. In the post-Golgi region, three distinct membrane compartments containing uroplakins were characterized: i) Small rounded vesicles, located close to the Golgi apparatus, were labelled weakly with anti-uroplakin antibodies and they possessed no plaques; we termed them “uroplakin-positive transporting vesicles” (UPTVs). ii) Spherical-to-flattened vesicles, termed “immature fusiform vesicles” (iFVs), were uroplakin-positive in their central regions and contained small urothelial plaques. iii) Flattened “mature fusiform vesicles” (mFVs) contained large plaques, which were densely labelled with anti-uroplakin antibodies. Endoytotic marker horseradish peroxidase was not found in these post-Golgi compartments. We propose a detailed model of de novo urothelial plaque formation in post-Golgi compartments: UPTVs carrying individual 16-nm particles detach from the Golgi apparatus and subsequently fuse into iFV. Concentration of 16-nm particles into plaques and removal of uroplakin-negative membranes takes place in iFVs. With additional fusions and buddings, iFVs mature into mFVs, each carrying two urothelial plaques toward the apical surface of the umbrella cell

    The structure and regulation of Cullin 2 based E3 ubiquitin ligases and their biological functions

    Get PDF
    corecore