345 research outputs found

    Cohomology Groups of Deformations of Line Bundles on Complex Tori

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    The cohomology groups of line bundles over complex tori (or abelian varieties) are classically studied invariants of these spaces. In this article, we compute the cohomology groups of line bundles over various holomorphic, non-commutative deformations of complex tori. Our analysis interpolates between two extreme cases. The first case is a calculation of the space of (cohomological) theta functions for line bundles over constant, commutative deformations. The second case is a calculation of the cohomologies of non-commutative deformations of degree-zero line bundles.Comment: 24 pages, exposition improved, typos fixe

    Moduli Stacks of Bundles on Local Surfaces

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    We give an explicit groupoid presentation of certain stacks of vector bundles on formal neighborhoods of rational curves inside algebraic surfaces. The presentation involves a M\"obius type action of an automorphism group on a space of extensions.Comment: submitted upon invitation to the 2011 Mirror Symmetry and Tropical Geometry Conference (Cetraro, Italy) volume of the Springer Lecture Notes in Mathematic

    Mirror duality and noncommutative tori

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    In this paper, we study a mirror duality on a generalized complex torus and a noncommutative complex torus. First, we derive a symplectic version of Riemann condition using mirror duality on ordinary complex tori. Based on this we will find a mirror correspondence on generalized complex tori and generalize the mirror duality on complex tori to the case of noncommutative complex tori.Comment: 22pages, no figure

    Tyrphostins that suppress the growth of human papilloma virus 16‐immortalized human keratinocytes

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    ABSTRACT Human papilloma virus 16 (HPV16) is considered to be the causative agent for cervical cancer, which ranks second to breast cancer in women's malignancies. In an attempt to develop drugs that inhibit the malignant transformation of HPV16-immortalized epithelial cells, we examined the effect of tyrphostins on such cells. We examined the effect of tyrphostins from four different families on the growth of HPV16-immortalized human keratinocytes (HF-1) cells. We found that they alter their cell cycle distribution, their morphology, and induce cell death by apoptosis. The effects of tyrphostins on HF-1 cells are different from their effects on normal keratinocytes. Growth suppression by AG555 and AG1478 is accompanied by 30% apoptosis in HF-1 cells, but this is not observed in normal keratinocytes. Tyrphostin treatment produces distinctive morphological changes in HF-1 cells and in normal keratinocytes; however, the culture organization of normal keratinocytes is less disrupted. These differential effects of the tyrphostins on HPV16-immortalized keratinocytes compared with their effects on normal keratinocytes suggests that these compounds are suitable candidates for the treatment of papilloma. Previous and present results indicate that group 1 tyrphostins, which inhibit Cdk2 activation, and group 2 tyrphostins, represented by AG1478, a potent epidermal growth factor receptor kinase inhibitor, induce cell cycle arrest; and, in the case of HF-1 cells, apoptosis and differentiation. Cells accumulate in the G 1 phase of the cell cycle at the expense of S and G 2 ϩ M. These compounds block the growth of normal keratinocytes without inducing apoptosis or differentiation, causing them to accumulate in G 1 . AG17, which belongs to group 4, exerts its antiproliferative effect mainly by increasing the fractions of cells in G 1 with a concomitant decrease in the fraction of cells in S and G 2 ϩ M

    Influence of highway 3D coordination on drivers' perception of horizontal curvature and available sight distance

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    "This paper is a preprint of a paper submitted to [journal] and is subject to Institution of Engineering and Technology Copyright. If accepted, the copy of record will be available at IET Digital Library"Drivers' road perception is an important human factor of comfort and safety on driving. Available sight distance of crest vertical curves superimposed on horizontal curves can be geometrically optimised by applying 3D coordination criteria. However, drivers might not perceive available sight distance improvements. Two approaches were used to investigate the effect of geometrical optimised design on perceived sharpness and visibility of isolated crest vertical curves overlapped with horizontal curves. A survey-based approach was used to evaluate subjective perception of 100 drivers. Three-dimensional renderings were displayed to subjects; who were asked to rank the curves by sharpness and sight distance. Moreover, 50 of those drivers previously participated on a driving simulation experiment involving the same curves, so objective driving data were collected too. Drivers' survey results indicate that driver's curve perception depends on the algebraic difference of grades while coordination of vertical and horizontal curves does not appear to affect this perception. On the other hand, the operating speeds on different curves were not statistically different from each other. Surprisingly, the operating speeds on a flat curve tended to be lower than on the vertical crest curves superimposed on the same horizontal curve. Likely causes are discussed in the paper.Moreno Chou, AT.; García García, A.; Camacho Torregrosa, FJ.; Llorca Garcia, C. (2013). Influence of highway 3D coordination on drivers' perception of horizontal curvature and available sight distance. IET Intelligent Transport Systems. 7(2):244-250. doi:10.1049/iet-its.2012.0146S24425072Hassan, Y., & Easa, S. M. (2000). Modeling of Required Preview Sight Distance. Journal of Transportation Engineering, 126(1), 13-20. doi:10.1061/(asce)0733-947x(2000)126:1(13)García, A. (2004). Discussion of «Optimal Vertical Alignment Analysis for Highway Design» by T. F. Fwa, W. T. Chan, and Y. P. Sim. Journal of Transportation Engineering, 130(1), 138-138. doi:10.1061/(asce)0733-947x(2004)130:1(138)Bidulka, S., Sayed, T., & Hassan, Y. (2002). Influence of Vertical Alignment on Horizontal Curve Perception: Phase I: Examining the Hypothesis. Transportation Research Record: Journal of the Transportation Research Board, 1796(1), 12-23. doi:10.3141/1796-02Hassan, Y., Sayed, T., & Bidulka, S. (2002). Influence of Vertical Alignment on Horizontal Curve Perception: Phase II: Modeling Perceived Radius. Transportation Research Record: Journal of the Transportation Research Board, 1796(1), 24-34. doi:10.3141/1796-03Hasan, M., Sayed, T., & Hassan, Y. (2005). Influence of vertical alignment on horizontal curve perception: effect of spirals and position of vertical curve. Canadian Journal of Civil Engineering, 32(1), 204-212. doi:10.1139/l04-090Wang, F., & Easa, S. M. (2009). Validation of Perspective-View Concept for Estimating Road Horizontal Curvature. Journal of Transportation Engineering, 135(2), 74-80. doi:10.1061/(asce)0733-947x(2009)135:2(74)Bella, F. (2007). Parameters for Evaluation of Speed Differential. Transportation Research Record: Journal of the Transportation Research Board, 2023(1), 37-43. doi:10.3141/2023-05Ben-Bassat, T., & Shinar, D. (2011). Effect of shoulder width, guardrail and roadway geometry on driver perception and behavior. Accident Analysis & Prevention, 43(6), 2142-2152. doi:10.1016/j.aap.2011.06.004Jia, L., Wang, J., & Lu, M. (2011). Using real-world data to calibrate a driving simulator measuring lateral driving behaviour. IET Intelligent Transport Systems, 5(1), 21-31. doi:10.1049/iet-its.2009.0094Antonson, H., Mårdh, S., Wiklund, M., & Blomqvist, G. (2009). Effect of surrounding landscape on driving behaviour: A driving simulator study. Journal of Environmental Psychology, 29(4), 493-502. doi:10.1016/j.jenvp.2009.03.005Land, M. F., & Lee, D. N. (1994). Where we look when we steer. Nature, 369(6483), 742-744. doi:10.1038/369742a0Zuriaga, A. M. P., García, A. G., Torregrosa, F. J. C., & D’Attoma, P. (2010). Modeling Operating Speed and Deceleration on Two-Lane Rural Roads with Global Positioning System Data. Transportation Research Record: Journal of the Transportation Research Board, 2171(1), 11-20. doi:10.3141/2171-02Kweon, B.-S., Ellis, C. D., Lee, S.-W., & Rogers, G. O. (2006). Large-Scale Environmental Knowledge. Environment and Behavior, 38(1), 72-91. doi:10.1177/001391650528009

    Assessing Graphical Robot Aids for Interactive Co-working

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    The shift towards more collaborative working between humans and robots increases the need for improved interfaces. Alongside robust measures to ensure safety and task performance, humans need to gain the confidence in robot co-operators to enable true collaboration. This research investigates how graphical signage can support human–robot co-working, with the intention of increased productivity. Participants are required to co-work with a KUKA iiwa lightweight manipulator on a manufacturing task. The three conditions in the experiment differ in the signage presented to the participants – signage relevant to the task, irrelevant to the task, or no signage. A change between three conditions is expected in anxiety and negative attitudes towards robots; error rate; response time; and participants’ complacency, suggested by facial expressions. In addition to understanding how graphical languages can support human–robot co-working, this study provides a basis for further collaborative research to explore human–robot co-working in more detail

    Upregulation of the cell-cycle regulator RGC-32 in Epstein-Barr virus-immortalized cells

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    Epstein-Barr virus (EBV) is implicated in the pathogenesis of multiple human tumours of lymphoid and epithelial origin. The virus infects and immortalizes B cells establishing a persistent latent infection characterized by varying patterns of EBV latent gene expression (latency 0, I, II and III). The CDK1 activator, Response Gene to Complement-32 (RGC-32, C13ORF15), is overexpressed in colon, breast and ovarian cancer tissues and we have detected selective high-level RGC-32 protein expression in EBV-immortalized latency III cells. Significantly, we show that overexpression of RGC-32 in B cells is sufficient to disrupt G2 cell-cycle arrest consistent with activation of CDK1, implicating RGC-32 in the EBV transformation process. Surprisingly, RGC-32 mRNA is expressed at high levels in latency I Burkitt's lymphoma (BL) cells and in some EBV-negative BL cell-lines, although RGC-32 protein expression is not detectable. We show that RGC-32 mRNA expression is elevated in latency I cells due to transcriptional activation by high levels of the differentially expressed RUNX1c transcription factor. We found that proteosomal degradation or blocked cytoplasmic export of the RGC-32 message were not responsible for the lack of RGC-32 protein expression in latency I cells. Significantly, analysis of the ribosomal association of the RGC-32 mRNA in latency I and latency III cells revealed that RGC-32 transcripts were associated with multiple ribosomes in both cell-types implicating post-initiation translational repression mechanisms in the block to RGC-32 protein production in latency I cells. In summary, our results are the first to demonstrate RGC-32 protein upregulation in cells transformed by a human tumour virus and to identify post-initiation translational mechanisms as an expression control point for this key cell-cycle regulator

    Revenue decentralization, central oversight and the political budget cycle : evidence from Israel

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    This paper examines whether revenue decentralization and direct external financial supervision affect the incidence and strength of political budget cycles, using a panel of Israeli municipalities during the period 1999-2009. We find that high dependence on central government transfers—as reflected in a low share of locally raised revenues in the municipality’s budget—exacerbates political budget cycles, while tight monitoring—exercised through central government appointment of external accountants to debt accumulating municipalities—eliminates them. These results suggest that political budget cycles can result from fiscal institutions that create soft budget constraints: that is, where incumbents and rational voters can expect that the costs of pre-election expansions will be partly covered later by the central government
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