Involutivity of integrals for sine-Gordon, modified KdV and potential KdV maps

Closed form expressions in terms of multi-sums of products have been given in \cite{Tranclosedform, KRQ} of integrals of sine-Gordon, modified Korteweg-de Vries and potential Korteweg-de Vries maps obtained as so-called $(p,-1)$-traveling wave reductions of the corresponding partial difference equations. We prove the involutivity of these integrals with respect to recently found symplectic structures for those maps. The proof is based on explicit formulae for the Poisson brackets between multi-sums of products.Comment: 24 page

The staircase method: integrals for periodic reductions of integrable lattice equations

We show, in full generality, that the staircase method provides integrals for mappings, and correspondences, obtained as traveling wave reductions of (systems of) integrable partial difference equations. We apply the staircase method to a variety of equations, including the Korteweg-De Vries equation, the five-point Bruschi-Calogero-Droghei equation, the QD-algorithm, and the Boussinesq system. We show that, in all these cases, if the staircase method provides r integrals for an n-dimensional mapping, with 2r<n, then one can introduce q<= 2r variables, which reduce the dimension of the mapping from n to q. These dimension-reducing variables are obtained as joint invariants of k-symmetries of the mappings. Our results support the idea that often the staircase method provides sufficiently many integrals for the periodic reductions of integrable lattice equations to be completely integrable. We also study reductions on other quad-graphs than the regular 2D lattice, and we prove linear growth of the multi-valuedness of iterates of high-dimensional correspondences obtained as reductions of the QD-algorithm.Comment: 40 pages, 23 Figure

Verkenning gevolgen van verliesnormen: technisch, economisch en maatschappelijk

In dit rapport wordt verslag gedaan van de resultaten van Cluster 5 van de Taakgroep "Normen" binnen het project "Evaluatie Meststoffenwet 2002". Centrale vraag die middels het deelproject Normen beantwoord dient te worden is of de verliesnormen die thans in de Meststoffenwet staan voor de jaren 2003 en verder aangepast moeten worden. Daarnaast is het nodig inzicht te hebben in de verwachte gevolgen van varianten van verliesnormen (aanscherping) voor de milieukwaliteit en voor de technische en economische prestaties van de bedrijven in de verschillende sectoren. De prognose wat betreft technische en economische prestaties van de bedrijven wordt in dit rapport gerapporteerd. : :Relevante vragen hierbij zijn: : :- Welke pakketten van maatregelen zijn op bedrijfsniveau nodig om verschillende varianten van verliesnormen te realiseren? : :- In welke mate leiden de maatregelen die op bedrijfsniveau nodig zijn om te voldoen aan varianten van verliesnormen tot hogere kosten door bedrijfsaanpassingen, teruglopende gewasopbrengsten en toenemende druk op mestmarkt? : :- Welke maatregelen worden naar verwachting ook daadwerkelijk doorgevoerd in de verschillende sectoren om aan de verliesnormen te kunnen voldoen en wat zijn hiervan de gevolgen voor de continuoteit van de bedrijven in de verschillende sectoren? : :- Wat zijn, uitgaande van de te verwachten ontwikkelingen in de sectoren, de sociaal-economische gevolgen van varianten van verliesnormen. Sociaal economische effecten betreffen daarbij gevolgen voor werkgelegenheid, bruto nationaal product, nationaal inkomen etc. : :Gezien de aard van de problematiek wordt in deze prognoses rekening gehouden met verschillen in grondsoort, bedrijfsopzet en sectoren. De uitkomsten van berekeningen voor de verschillende varianten worden gerelateerd aan een referentievariant

Effect van emissie-arme maatregelen op milieu en inkomen

Resultaten ervan zijn gebruikt in een studie naar de kosten van deze systemen en de mogelijke vermindering van de ammoniakemissie

The chemical potential of the electron gas on a one dimensional lattice

The chemical potential of the electron gas on a one-dimensional lattice is determined within the discrete Hubbard model. The result will have applications in studies of transport properties of quasi one-dimensional organic conductors such as the Bechgaard salts.Comment: 4 pages,plain TeX,presented at the 9 National Congress of Yugoslav Physicists,held in May 1995.,and published in the proceedings.The author can be contacted at: [email protected]

Antimicrobial resistance conferred by OXA-48 β-lactamases:towards a detailed mechanistic understanding

OXA-48-type β-lactamases are now routinely encountered in bacterial infections caused by carbapenem-resistant Enterobacterales. These enzymes are of high and growing clinical significance due to the importance of carbapenems in treatment of health care-associated infections by Gram-negative bacteria, the wide and increasing dissemination of OXA-48 enzymes on plasmids, and the challenges posed by their detection. OXA-48 confers resistance to penicillin (which is efficiently hydrolyzed) and carbapenem antibiotics (which is more slowly broken down). In addition to the parent enzyme, a growing array of variants of OXA-48 is now emerging. The spectrum of activity of these variants varies, with some hydrolyzing expanded-spectrum oxyimino-cephalosporins. The growth in importance and diversity of the OXA-48 group has motivated increasing numbers of studies that aim to elucidate the relationship between structure and specificity and establish the mechanistic basis for β-lactam turnover in this enzyme family. In this review, we collate recently published structural, kinetic, and mechanistic information on the interactions between clinically relevant β-lactam antibiotics and inhibitors and OXA-48 β-lactamases. Collectively, these studies are starting to form a detailed picture of the underlying bases for the differences in β-lactam specificity between OXA-48 variants and the consequent differences in resistance phenotype. We focus specifically on aspects of carbapenemase and cephalosporinase activities of OXA-48 β-lactamases and discuss β-lactamase inhibitor development in this context. Throughout the review, we also outline key open research questions for future investigation

High-techbedrijf voldoet aan verliesnormen in 2001

Het high-techbedrijf van de Waiboerhoeve voldoet in 2001 precies aan de stikstofverliesnorm van MINAS

Higher analogues of the discrete-time Toda equation and the quotient-difference algorithm

The discrete-time Toda equation arises as a universal equation for the relevant Hankel determinants associated with one-variable orthogonal polynomials through the mechanism of adjacency, which amounts to the inclusion of shifted weight functions in the orthogonality condition. In this paper we extend this mechanism to a new class of two-variable orthogonal polynomials where the variables are related via an elliptic curve. This leads to a `Higher order Analogue of the Discrete-time Toda' (HADT) equation for the associated Hankel determinants, together with its Lax pair, which is derived from the relevant recurrence relations for the orthogonal polynomials. In a similar way as the quotient-difference (QD) algorithm is related to the discrete-time Toda equation, a novel quotient-quotient-difference (QQD) scheme is presented for the HADT equation. We show that for both the HADT equation and the QQD scheme, there exists well-posed $s$-periodic initial value problems, for almost all \s\in\Z^2. From the Lax-pairs we furthermore derive invariants for corresponding reductions to dynamical mappings for some explicit examples.Comment: 38 page

Arbeidsvergoeding high-techbedrijf 50 eurocent per uur in 2002

De kostprijs van het high-techbedrijf is 1,5 eurocent hoger dan van vergelijkbare bedrijven