16,183 research outputs found

    General solution for Hamiltonians with extended cubic and quartic potentials

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    We integrate with hyperelliptic functions a two-particle Hamiltonian with quartic potential and additionnal linear and nonpolynomial terms in the Liouville integrable cases 1:6:1 and 1:6:8.Comment: LaTex 2e. To appear, Theoretical and Mathematical Physics 200

    GreenPhylDB v2.0: An improved database for plant functional genomics

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    Poster presented at 2009 Annual Research Meeting of the Generation Challenge Programme. Bamako (Mali), 20-23 September 200

    Integration of a generalized H\'enon-Heiles Hamiltonian

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    The generalized H\'enon-Heiles Hamiltonian H=1/2(PX2+PY2+c1X2+c2Y2)+aXY2bX3/3H=1/2(P_X^2+P_Y^2+c_1X^2+c_2Y^2)+aXY^2-bX^3/3 with an additional nonpolynomial term μY2\mu Y^{-2} is known to be Liouville integrable for three sets of values of (b/a,c1,c2)(b/a,c_1,c_2). It has been previously integrated by genus two theta functions only in one of these cases. Defining the separating variables of the Hamilton-Jacobi equations, we succeed here, in the two other cases, to integrate the equations of motion with hyperelliptic functions.Comment: LaTex 2e. To appear, Journal of Mathematical Physic

    Completeness of the cubic and quartic H\'enon-Heiles Hamiltonians

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    The quartic H\'enon-Heiles Hamiltonian H=(P12+P22)/2+(Ω1Q12+Ω2Q22)/2+CQ14+BQ12Q22+AQ24+(1/2)(α/Q12+β/Q22)γQ1H = (P_1^2+P_2^2)/2+(\Omega_1 Q_1^2+\Omega_2 Q_2^2)/2 +C Q_1^4+ B Q_1^2 Q_2^2 + A Q_2^4 +(1/2)(\alpha/Q_1^2+\beta/Q_2^2) - \gamma Q_1 passes the Painlev\'e test for only four sets of values of the constants. Only one of these, identical to the traveling wave reduction of the Manakov system, has been explicitly integrated (Wojciechowski, 1985), while the three others are not yet integrated in the generic case (α,β,γ)(0,0,0)(\alpha,\beta,\gamma)\not=(0,0,0). We integrate them by building a birational transformation to two fourth order first degree equations in the classification (Cosgrove, 2000) of such polynomial equations which possess the Painlev\'e property. This transformation involves the stationary reduction of various partial differential equations (PDEs). The result is the same as for the three cubic H\'enon-Heiles Hamiltonians, namely, in all four quartic cases, a general solution which is meromorphic and hyperelliptic with genus two. As a consequence, no additional autonomous term can be added to either the cubic or the quartic Hamiltonians without destroying the Painlev\'e integrability (completeness property).Comment: 10 pages, To appear, Theor.Math.Phys. Gallipoli, 34 June--3 July 200

    Detection and construction of an elliptic solution to the complex cubic-quintic Ginzburg-Landau equation

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    In evolution equations for a complex amplitude, the phase obeys a much more intricate equation than the amplitude. Nevertheless, general methods should be applicable to both variables. On the example of the traveling wave reduction of the complex cubic-quintic Ginzburg-Landau equation (CGL5), we explain how to overcome the difficulties arising in two such methods: (i) the criterium that the sum of residues of an elliptic solution should be zero, (ii) the construction of a first order differential equation admitting the given equation as a differential consequence (subequation method).Comment: 12 pages, no figure, to appear, Theoretical and Mathematical Physic

    The adherent/invasive escherichia coli (AIEC) strain LF82 invades and persists in human prostate cell lineRWPE-1 activating a strong inflammatory response

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    Adherent/invasive Escherichia coli (AIEC) strains have recently been receiving increased attention because they are more prevalent and persistent in the intestine of Crohn's disease (CD) patients than in healthy subjects. Since AIEC strains show a high percentage of similarity to extraintestinal pathogenic E. coli (ExPEC), neonatal meningitis-associated E. coli (NMEC), and uropathogenic E. coli (UPEC) strains, here we compared AIEC strain LF82 with a UPEC isolate (strain EC73) to assess whether LF82 would be able to infect prostate cells as an extraintestinal target. The virulence phenotypes of both strains were determined by using the RWPE-1 prostate cell line. The results obtained indicated that LF82 and EC73 are able to adhere to, invade, and survive within prostate epithelial cells. Invasion was confirmed by immunofluorescence and electron microscopy. Moreover, cytochalasin D and colchicine strongly inhibited bacterial uptake of both strains, indicating the involvement of actin microfilaments and microtubules in host cell invasion. Moreover, both strains belong to phylogenetic group B2 and are strong biofilm producers. In silico analysis reveals that LF82 shares with UPEC strains several virulence factors: namely, type 1 pili, the group II capsule, the vacuolating autotransporter toxin, four iron uptake systems, and the pathogenic island (PAI). Furthermore, compared to EC73, LF82 induces in RWPE-1 cells a marked increase of phosphorylation of mitogen-activated protein kinases (MAPKs) and of NF-κB already by 5 min postinfection, thus inducing a strong inflammatory response. Our in vitro data support the hypothesis that AIEC strains might play a role in prostatitis, and, by exploiting host-cell signaling pathways controlling the innate immune response, likely facilitate bacterial multiplication and dissemination within the male genitourinary trac

    Meromorphic traveling wave solutions of the complex cubic-quintic Ginzburg-Landau equation

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    We look for singlevalued solutions of the squared modulus M of the traveling wave reduction of the complex cubic-quintic Ginzburg-Landau equation. Using Clunie's lemma, we first prove that any meromorphic solution M is necessarily elliptic or degenerate elliptic. We then give the two canonical decompositions of the new elliptic solution recently obtained by the subequation method.Comment: 14 pages, no figure, to appear, Acta Applicandae Mathematica

    Particle Flux in the deep Sargasso Sea : the 35-Year Oceanic Flux Program time series

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    Author Posting. © The Oceanography Society, 2014. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 27, no. 1 (2014): 142–147, doi:10.5670/oceanog.2014.17.The Oceanic Flux Program (OFP) sediment trap time series, the longest running time series of its kind, has continuously measured particle fluxes in the deep Sargasso Sea since 1978. OFP results provided the first direct observation of seasonality in the deep ocean, and they have documented the tight coupling between deep fluxes and upper ocean processes and the intensity of biological reprocessing of sinking flux in the ocean interior. The synergy among OFP and other research programs co-located at the Bermuda time-series site has provided unprecedented opportunities to study the linkages among ocean physics, biology, and chemistry; particle flux generation; and particle recycling in the ocean interior. The OFP time series is beginning to reveal how basin-scale climatic forcing, such as the North Atlantic Oscillation, affects the deep particle flux.We gratefully acknowledge the National Science Foundation’s continuous financial support of the Oceanic Flux Program time series for the past 35 years, most recently by NSF grants OCE 1234294 and OCE 0927098

    Cultural determinants of workplace arbitration in the U.S. and Italy. WP CSDLE “Massimo D’Antona”.INT – 112/2014

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    Globalization of employment is making knowledge of labor and employment law of all nations an imperative. At the same time, comparative legal studies can help nations learn from one another and improve on existing legal systems. As the United States Supreme Court is hurtling U.S. employment law into private dispute resolution and the Italian labor law system is under substantial pressure for reform as a result of economic stresses, a comparative study of workplace arbitration in the two countries is timely. This article looks at the law and impact of workplace arbitration in the United States and Italy with a goal of analyzing the influences that led to the current systems and determining whether the countries can derive any useful lessons from one another. First, the article looks briefly at the labor and employment law systems in the two countries. This analysis lays the backdrop for a discussion of the evolution and use of arbitration in the two countries. The article then moves to an analysis of the similarities and differences between arbitration in Italy and the U.S. and the reasons for those differences. Finally the article focuses on lessons that can be drawn from the two systems. The employment arbitration system in the U.S. is currently weighted in favor of employers, and could learn from the Italian protection of workers. The article suggests several modifications that would provide better balance in the current system. But the article concludes that the historical and cultural forces that have shaped arbitration in the two countries make it unlikely that either will change significantly in the near future
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