Beeinflussen verschiedene Volatilenmuster die Wirtspflanzenwahl unterirdisch lebender Insekten?

Cockchafers of the genus Melolontha (Coleoptera: Scarabaeidae) can be severe pests in forestry, agriculture and horticulture. Gradation of the two most important species, the forest cockchafer M. hippocastani FABR. and the European cockchafer M. melolontha L., occurs currently in several parts of central Europe. Orientation behaviour of the adult beetles has been the focus of recent studies (REINECKE et al. 2002 a, b, 2005). However, especially the larvae are dreaded because their belowground damage is not visible directly after feeding. There are a lot of speculations about belowground living insects and their way of living, but until now there were not that many experimental investigations. A rather unknown topic is the orientation behaviour of soil living organisms, which is also subject of some publications (HORBER 1954, HAUSS & SCHÜTTE 1976, HASLER 1986, HIBBARD et al. 1994, JEWETT & BJOSTAD 1996, BERNKLAU & BJOSTAD 1998A, BERNKLAU & BJOSTAD 1998B, BERNKLAU et al. 2005).Zum besseren Verständnis der Orientierung und Fraßpräferenz von Maikäferlarven Melolontha hippocastani FABR. (Coleoptera: Scarabaeidae) im Boden wurden Wahltests durchgeführt. Den Larven von M. hippocastani wurden Karotten (Daucus carota ssp. sativus) und Eichenwurzeln (Quercus sp.) zur Auswahl angeboten. Die Duftstoffe von Karotte und Eichenwurzel wurden auf Aktivkohle gesammelt und mit Gaschromatographie – Massenspektroskopie untersucht (GC-MS). Unverletzte Karotten sowie Eichenwurzeln unterschieden sich in ihr n Volatilenmustern deutlich voneinander. Darüber hinaus konnten Unterschiede im Volatilenmuster unverletzter, mechanisch verletzter sowie angefressener Wurzeln nachgewiesen werden

Agglomeration and population ageing in a two region model of exogenous growth

This article investigates the effects of introducing demography into the New Economic Geography. We generalize the constructed capital approach, which relies on infinite individual planning horizons, by introducing mortality. The resulting overlapping generation framework with heterogeneous individuals allows us to study the effects of ageing on agglomeration processes by analytically identifying the level of trade costs that triggers catastrophic agglomeration. Interestingly, this threshold value is rather sensitive to changes in mortality. In particular, the introduction of a positive mortality rate makes the symmetric equilibrium more stable and therefore counteracts agglomeration tendencies. In sharp contrast to other New Economic Geography approaches, this implies that deeper integration is not necessarily associated with higher interregional inequality.Agglomeration, New Economic Geography, Trade and Growth, Constructed Capital Model, Population Ageing.

Agglomeration and population ageing in a two region model of exogenous growth

This article investigates the effects of introducing demography into the New Economic Geography. We generalize the constructed capital approach, which relies on infinite individual planning horizons, by introducing mortality. The resulting overlapping generation framework with heterogeneous individuals allows us to study the effects of ageing on agglomeration processes by analytically identifying the level of trade costs that triggers catastrophic agglomeration. Interestingly, this threshold value is rather sensitive to changes in mortality. In particular, the introduction of a positive mortality rate makes the symmetric equilibrium more stable and therefore counteracts agglomeration tendencies. In sharp contrast to other New Economic Geography approaches, this implies that deeper integration is not necessarily associated with higher interregional inequality

Agglomeration processes in ageing societies

This article investigates agglomeration processes in ageing societies by introducing an overlapping generation structure into a New Economic Geography model. Whether higher economic integration leads to spatial concentration of economic activity crucially hinges on the economies' demographic properties. While population aging as represented by declining birth rates strengthens agglomeration processes, declining mortality rates weaken them. This is due to the fact that we allow for nonconstant population size. In particular, we show that population growth acts as an important dispersion force that augments the distributional effects on agglomeration processes resulting from the turnover of generations

Time Series Analysis of Noaa Avhrr Derived Vegetation Cover as a Means to Extract Proportions of Permanent and Seasonal Components at Pixel Level

The scope of this study was to find a simple and robust technique to analyze a 16 years time se-ries (totalling 576 decades) of NOAA-AVHRR derived Green Vegetation Fraction (GVF) for de-scribing the bio-physical properties of the observed vegetation canopy as a function of its compo-sition in terms of a seasonally changing vegetation component and a permanent vegetation com-ponent. The principal idea behind the analysis is to use a simple model of an annual vegetation growth cycle per pixel, which is fitted against the available time sequence of data, and interpret on one side the parameters of the fit and on the other side the residuals of the original versus the fitted data. For simplicity reasons this part is represented by a sinus curve with a fixed wavelength of one year. This model allows splitting of the timely resolved vegetation signal into two compo-nents in vegetation appearance. One represents a "permanent background" throughout the year, which is the off-set between the 0 level representing the absence of vegetation cover and the minimum of the modelled seasonal change. The second represents the difference between the maximum and the minimum vegetation cover modelled every year. This technique has been ap-plied to the entire Mediterranean region covered by a NOAA AVHRR time series. The derived pro-portions of permanent and seasonal vegetation components have been finally interpreted on the European CORINE land cover class ‘Olive grove’, assessing the variation of permanent and sea-sonal vegetation components as function of management intensity, leading to a distinction of dif-ferent olive grove management intensity classes within the limits of the CORINE class. The olive class has been chosen as test case because of its well known linkages between the evergreen component represented by the olive trees and the more or less pronounced presence of annual herbaceous understory.JRC.H.5-Rural, water and ecosystem resource

Machine Learning-powered Course Allocation

We introduce a machine learning-powered course allocation mechanism. Concretely, we extend the state-of-the-art Course Match mechanism with a machine learning-based preference elicitation module. In an iterative, asynchronous manner, this module generates pairwise comparison queries that are tailored to each individual student. Regarding incentives, our machine learning-powered course match (MLCM) mechanism retains the attractive strategyproofness in the large property of Course Match. Regarding welfare, we perform computational experiments using a simulator that was fitted to real-world data. Our results show that, compared to Course Match, MLCM increases average student utility by 4%-9% and minimum student utility by 10%-21%, even with only ten comparison queries. Finally, we highlight the practicability of MLCM and the ease of piloting it for universities currently using Course Match

Rezension: HESSKY, REGINA, & ETTINGER, STEFAN (1997), Deutsche Redewendungen. Ein Wörter- und Übungsbuch für Fortgeschrittene

Mit der vorliegenden Publikation gelingen dem Autorenteam Regina Hessky und Stefan Ettinger einige wesentliche Neuerungen gegenüber herkömmlichen Idiomatiksammlungen: So werden beispielsweise Redensarten nicht einfach alphabetisch gesammelt und angeordnet, sondern zu inhaltlich zusammengehörenden Gruppen gebündelt. Daß es bei dieser Vorgangsweise mancherorts zu Wiederholungen kommen muß, läßt sich u. a. auf positive oder negative Konnotationen zurückführen, welche sich am besten durch eine "ideographische Gliederung" (vgl. XI) vermeiden lassen

Rezension: BRAND, LINDA M., JUTTA KRESIN-MURAKAMI & KARL PECHATSCHEK: Die Schöne ist angekommen. Ein Grammatikkrimi

Daß Grammatik auch spannend sein kann, beweist Die Schöne ist angekommen. Verfaßt in der neuen deutschen Rechtschreibung, bietet dieser Grammatikkrimi eine originelle Kombination zwischen Grammatikvermittlung und Krimi. Das Üb ungsbuch ist unterteilt in zehn Kapitel mit insgesamt 20 ausgewählten Schwerpunkten zur deutschen Grammatik und wendet sich an Lernende zu Beginn der Mittelstufe als Wiederholung des Grammatikpensums der Grundstufe oder aber an Grundstufenlerner zur Vorbereitung auf die Prüfung "Zertifikat Deutsch als Fremdsprache". Dem Vorwort des Autorenteams kann entnommen werden, daß die Auswahl der grammatischen Schwerpunkte und des Wortschatzes sich an den Anforderungen des "Zertifikats Deutsch als Fremdsprache" orientiert. Im Anhang wird zudem der Inhalt der erzählten Geschichte in 60 Testfragen zusammengefaßt, welche wiederum dem Prüfungsteil "Strukturen und Wortschatz" entsprechen