1,894 research outputs found

    On the second gaussian map for curves on a K3 surface

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    By a theorem of Wahl, for canonically embedded curves which are hyperplane sections of K3 surfaces, the first gaussian map is not surjective. In this paper we prove that if C is a general hyperplane section of high genus (greater than 280) of a general polarized K3 surface, then the second gaussian map of C is surjective. The resulting bound for the genus g of a general curve with surjective second gaussian map is decreased to g >152.Comment: final version, to appear in Nagoya Mathematical Journa

    Prym map and second gaussian map for Prym-canonical line bundles

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    We show that the second fundamental form of the Prym map lifts the second gaussian map of the Prym-canonical bundle. We prove, by degeneration to binary curves, that this gaussian map is surjective for the general point [C,A] of R_g for g > 19.Comment: Final version. To appear in Advances in Mathematic

    When Stackelberg and Cournot Equilibria Coincide

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    We compare two-stage Stackleberg with Cournot equilibrium under the assumption of quantity competition and homogeneous goods.  We show that, when the curvature of the inverse market demand equals the total number of firms in the industry, the outcome of the two games coincides.

    PVT1: a rising star among oncogenic long non-coding RNAs

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    It is becoming increasingly clear that short and long noncoding RNAs critically participate in the regulation of cell growth, differentiation, and (mis)function. However, while the functional characterization of short non-coding RNAs has been reaching maturity, there is still a paucity of well characterized long noncoding RNAs, even though large studies in recent years are rapidly increasing the number of annotated ones. The long noncoding RNA PVT1 is encoded by a gene that has been long known since it resides in the well-known cancer risk region 8q24. However, a couple of accidental concurrent conditions have slowed down the study of this gene, that is, a preconception on the primacy of the protein-coding over noncoding RNAs and the prevalent interest in its neighbor MYC oncogene. Recent studies have brought PVT1 under the spotlight suggesting interesting models of functioning, such as competing endogenous RNA activity and regulation of protein stability of important oncogenes, primarily of the MYC oncogene. Despite some advancements in modelling the PVT1 role in cancer, there are many questions that remain unanswered concerning the precise molecular mechanisms underlying its functioning

    On totally geodesic submanifolds in the Jacobian locus

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    We study submanifolds of A_g that are totally geodesic for the locally symmetric metric and which are contained in the closure of the Jacobian locus but not in its boundary. In the first section we recall a formula for the second fundamental form of the period map due to Pirola, Tortora and the first author. We show that this result can be stated quite neatly using a line bundle over the product of the curve with itself. We give an upper bound for the dimension of a germ of a totally geodesic submanifold passing through [C] in M_g in terms of the gonality of C. This yields an upper bound for the dimension of a germ of a totally geodesic submanifold contained in the Jacobian locus, which only depends on the genus. We also study the submanifolds of A_g obtained from cyclic covers of the projective line. These have been studied by various authors. Moonen determined which of them are Shimura varieties using deep results in positive characteristic. Using our methods we show that many of the submanifolds which are not Shimura varieties are not even totally geodesic.Comment: To appear on International Journal of Mathematic

    Optimal Corporation Tax: An I.O. Approach

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    Theory predicts that optimal effective corporation tax rates will benegatively related to industry specific sunk costs, and hence industryconcentration. Governments should tax industries with monopolistic powersoftly. Evidence suggests that this Schumpeterian (1942) principle ofcorporate taxation was used widely across industries in France, Italy and theUK in the 1990s.Effective Corporation Tax Rate, Industry Sunk Costs,Industry Concentration.

    Interaction of mycobacterium tuberculosis with the host cells: a focus in the molecular mechanism involved in trafficking and autophagy

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    Tuberculosis (TB) is an ancient disease remaining a serious health threat worldwide. It is caused by Mycobacterium tuberculosis (Mtb), an acid-fast bacilli, non-sporulated, slow-growing, immobile and aerobic. The pathogenesis of the disease is based on its ability to multiply and survive within phagocytic cells of the host, particularly macrophages and monocytes. The majority (90 %) of infected humans have a ?latent infection?, meaning they efficiently contain but do not spread the bacteria; they are infected but asymptomatic and not contagious. However the remaining 10 % have a lifetime risk of reactivating the infection and developing active tuberculosis (Sakamoto, 2012). The great destructive impact on public health, the co-infection with the human immunodeficiency virus (HIV) and the appearance of drug resistant strains of Mtb are demanding the development of new tools for prevention and treatment.During the last decade a greater understanding on the human immune response to Mtb infection as well as the contribution of factors linked to the pathogenesis of the disease has been achieved. Although the knowledge about the human immune response against Mtb as well as the contribution of factors linked to the pathogenesis of the disease have markedly increased in the last year, a deeper understanding of its immunopathogenesis will lead to the identification of new drugs and the development of effective vaccines.Fil: Zarelli, Valeria Eugenia Paola. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Mendoza. Instituto de HistologĂ­a y EmbriologĂ­a de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias MĂ©dicas. Instituto de HistologĂ­a y EmbriologĂ­a de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Giai, Constanza. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Mendoza. Instituto de HistologĂ­a y EmbriologĂ­a de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias MĂ©dicas. Instituto de HistologĂ­a y EmbriologĂ­a de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Colombo, Maria Isabel. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Mendoza. Instituto de HistologĂ­a y EmbriologĂ­a de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias MĂ©dicas. Instituto de HistologĂ­a y EmbriologĂ­a de Mendoza Dr. Mario H. Burgos; Argentin

    Impact of M&A on the R&D process. An empirical analysis of the role of technological and market relatedness, The

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    While the impact of M&A on R&D and innovation examined at the aggregate level left inconclusive evidence, we find that at the level of the R&D process both the technological and the market relatedness between the target and the acquirer are helpful dimensions to identify effects. Using information on 31 in-depth cases of individual M&A deals we show that technological relatedness between M&A partners directly affects the inputs and organizational structure of the R&D process. M&A partners that operate in the same technological fields tend to reduce their R&D effort and rationalize the R&D process after the M&A compared to firms active in complementary technological fields that merge. These firms will furthermore face less technological competition in the technology market, but risk creating a more bureaucratic R&D process with a less motivated workforce. Market relatedness between partners, while having comparable aggregate effects on the R&D process, operates on different dimensions of the R&D process. Former rivals that engage in a M&A are significantly less likely to expand into new R&D fields or leverage their technological competences across the products and markets of the new entity. Non-rival firms that join forces, in contrast, significantly increase R&D output and productivity through these activities.M&A; R&D; scale and scope; market relatedness; technological relatedness;

    On the Koszul cohomology of canonical and Prym-canonical binary curves

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    In this paper we study Koszul cohomology and the Green and Prym-Green conjectures for canonical and Prym-canonical binary curves. We prove that if property NpN_p holds for a canonical or a Prym-canonical binary curve of genus gg then it holds for a generic canonical or Prym-canonical binary curve of genus g+1g+1. We also verify the Green and Prym-Green conjectures for generic canonical and Prym-canonical binary curves of low genus (6≤g≤156\leq g\leq 15, g≠8g\neq 8 for Prym-canonical and 3≤g≤123\leq g\leq 12 for canonical).Comment: Final version. To appear in the Bulletin of the London Mathematical Societ
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