Liaison and Castelnuovo-Mumford regularity

In this article we establish bounds for the Castelnuovo-Mumford regularity of projective schemes in terms of the degrees of their defining equations. The main new ingredient in our proof is to show that generic residual intersections of complete intersection rational singularities again have rational singularities. When applied to the theory of residual intersections this circle of ideas also sheds new light on some known classes of free resolutions of residual ideals.Comment: 19 pages. To appear in "American Journal of Mathematics

SNUS-2.5, a Multimoment Analysis of Road Demand, Accidents and their Severity in Germany, 1968 – 1989

The present article presents an improved and refined version of the SNUS-1 model (GAUDRY and BLUM 1993) documented only in French. The greatest difficulty faced in the development of the model did not have to do with structure – the multilevel structure is straightforward – but with the specification of the employment activity variable, due to the specifics of the German economy,and with the proper formulation of the role of vehicle stocks in the road demand models. Moreover,we consider the following aspects to be special in the context of an analysis of Germany: • there exist no general speed limits on motorways, i.e. about 70% allow unlimited speed today,and in the Sixties, when our analysis starts, this share was even higher; • the country is large compared with other regions were the DRAG-methodology is employed, and it possesses high car ownership levels and an important car industry that sees the German infrastructure as an appropriate testing ground; • Germany is poly-central, its infrastructure resembles a grid, whereas France’s is almost a huband-spoke system, as compared for instance to Norway’s line; • unification is not yet included because of lagging data availability and, thus, problems to compensate for the structural break in data series.Classification-JEL:

Tie Turning Box-Cox including Quadratic Forms in Regression

In a regression model where a Box-Cox transformation is used on a positive independent variable X which appears only once in the equation, the effect of X on the dependent variable Y is either strictly increasing or decreasing over the whole range of X , since the transformation is a monotonic function of X , increasing or decreasing depending on the Box-Cox parameter ë. This paper considers the case where the variable X appears twice in the regression with two different Box-Cox parameters 1 ë and 2 ë , to allow a turning point in Y which can be a maximum or minimum. First and second-order conditions for the critical point are derived. This general specification includes as a special case the quadratic form in X where 1 ë and 2 ë are set equal to 1 and 2, respectively. If, instead of using the Box-Cox transformations, one uses simple powers of X , this form is equivalent to the Box-Cox form except that neither 1 ë nor 2 ë can be equal to zero, since in this case 1 ë X or 2 ë X reduces to a constant of value 1.Box-Cox Transformation, Quadratic Form, Asymmetric U-shaped Forms, Regression. Classification-JEL :

Was kennzeichnet "gute" Betreuung bei berufsbegleitenden Studiengängen im Blended-Learning-Format? Tragweite verschiedener Betreuungskomponenten und ihr Transfer auf andere Studiengänge

An der Pädagogischen Hochschule Ludwigsburg wurde im Jahre 2003 ein weiterbildender Masterstudiengang Bildungsmanagement installiert und im Jahr 2011 um einen zweiten Masterstudiengang International Education Management ergänzt. Beide Studiengänge sind als berufsbegleitende Blended-Learning-Studiengänge konzipiert. Ausgehend von diesem Beispiel fokussiert der Beitrag die generelle Diskussion um die Übertragbarkeit von Betreuungskonzepten sowie deren strategischen Ausrichtung. Hierzu werden Ergebnisse einer empirischen Erhebung vorgestellt, die diese Frage aus studentischer Perspektive beleuchten. In beiden Studiengängen wurden die Studierenden hinsichtlich ihrer Einschätzung der einzelnen Betreuungskomponenten befragt. Damit soll ermittelt werden, was eine "gute" Betreuung aus der Sicht von Studierenden auszeichnet und inwieweit ggf. Unterschiede zwischen "nationalen" und "internationalen" Studierenden festzustellen sind. (DIPF/Autor

Photorefractive properties of lithium niobate crystals doped with manganese

The photorefractive properties of lithium niobate crystals doped with manganese (Mn) have been investigated. It is found that the effect of dark decay due to electron tunneling, which is the limiting factor of the highest practical doping level, is less in LiNbO_3:Mn than in LiNbO_3:Fe , and higher doping levels can be used in LiNbO_3:Mn to achieve larger dynamic range and sensitivity for holographic applications. The highest practical doping level in LiNbO_3:Mn has been found to be ~0.5 wt.% MnCO_3, and refractive-index changes and sensitivities up to 1.5X10^-3 and 1.3 cm/J are measured for extraordinarily polarized light of the wavelength 458 nm. It has been found that, in terms of both dynamic range (or refractive-index change) and sensitivity, the optimal oxidation state is highly oxidized. The distribution coefficient of Mn has been determined to be ~1. Absorption measurements are used to obtain more information about charge-transport parameters. The material is excellently suited for holographic recording with blue light. The hologram quality is outstanding because holographic scattering is much weaker compared with that in, e.g., iron-doped lithium niobate. Thermal fixing has been successfully demonstrated in LiNbO_3:Mn crystals

Isolation of three novel rat and mouse papillomaviruses and their genomic characterization.

Despite a growing knowledge about the biological diversity of papillomaviruses (PV), only little is known about non-human PV in general and about PV mice models in particular. We cloned and sequenced the complete genomes of two novel PV types from the Norway rat (Rattus norvegicus; RnPV2) and the wood mouse (Apodemus sylvaticus; AsPV1) as well as a novel variant of the recently described MmuPV1 (originally designated as MusPV) from a house mouse (Mus musculus; MmuPV1 variant). In addition, we conducted phylogenetic analyses using a systematically representative set of 79 PV types, including the novel sequences. As inferred from concatenated amino acid sequences of six proteins, MmuPV1 variant and AsPV1 nested within the Beta+Xi-PV super taxon as members of the Pi-PV. RnPV2 is a member of the Iota-PV that has a distant phylogenetic position from Pi-PV. The phylogenetic results support a complex scenario of PV diversification driven by different evolutionary forces including co-divergence with hosts and adaptive radiations to new environments. PV types particularly isolated from mice and rats are the basis for new animal models, which are valuable to study PV induced tumors and new treatment options

Food supply modifies the trade-off between past and future reproduction in a sexual parasite-host system ( Rana esculenta, Rana lessonae )

Life history theory is concerned with the costs of survival, growth and reproduction under different ecological conditions and the allocation of resources to meet these costs. Typical approaches used to address these topics include manipulation of food resources, followed by measures of subsequent reproductive traits, and measures of the relationship between current and future reproductive investment. Rarely, however, do studies test for the interaction of past investment, present resource availability and future investment simultaneously. Here, we investigate this interaction in females of a sexual parasite-host system consisting of the hybridogenetic frog Rana esculenta (E) and one of its parental species Rana lessonae (L). We kept females from each of two groups (with or without previous reproduction) under two food treatments (low or high) and regularly recorded their growth as well as their body condition and hormone titres as measures of future reproductive condition. After keeping them in hibernation until the following spring, we exposed the females to males, recorded whether they spawned or not and related this response to their condition in the previous autumn. Past reproduction negatively affected growth during summer and condition during autumn which, in turn, reduced the following year's reproductive output. These costs of previous reproduction were less pronounced under the high than under the low food treatment and lower in R. lessonae than in R. esculenta. Increasing food supply improved reproductive condition more in L than in E females. These species differences in reproductive costs and food requirements provide a mechanistic explanation for why E females skip annual reproduction almost twice as often as L females. Since R. esculenta is a sexual parasite that depends on R. lessonae for successful reproduction, these species-specific life history patterns not only affect individual fitness but also the spatial structure and temporal dynamics of mixed LE population

Ein analytisches Modell für die Blutdruckübertragungsstrecke der invasiven Blutdruckmessung mit externer Flüssigkeitskopplung

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Die invasive Blutdruckmessung spielt in der Anästhesie und in der Intensivmedizin eine wichtige Rolle. Im klinischen Alltag wird vorwiegend das preisgünstige extrakorporale Blutdruckmeßverfahren mit einem externen Einwegtransducer eingesetzt. Die Qualität dieses Verfahrens hängt im wesentlichen von dem Druckübertragungsverhalten der Meßstrecke ab, welche hauptsächlich aus dem Katheter, den Verlängerungsschläuchen, der Flüssigkeitssäule und dem Transducer besteht. Zusätzlich beeinflussen in der Flüssigkeitssäule vorhandene Luftblasen die Druckübertragungsqualität. In diesem Beitrag wird eine analytische Methode zur Bestimmung der Übertragungseigenschaften dieses Blutdruckmeßsystems anhand eines erweiterten neuen Modell vorgestellt. In ihm sind alle wichtigen Bestandteile der Druckübertragungsstrecke hinsichtlich ihrer Geometrie und Materialeigenschaften berücksichtigt