Ein bedeutender Schädling im ökologischen Landbau: Meloidogyne hapla Chitwood

Dieses Informationsblatt möchte Landwirte und Berater über den Nördlichen Wurzelgallennematoden Meloidogyne hapla informieren. Dieser Nematode verursacht vor allem im ökologischen Landbau zunehmend Schäden an Gemüse und Kartoffeln. M. hapla ist die in Mitteleuropa am häufigsten vorkommende Meloidogyne-Art. Sie kann vor allem auf leichten Böden beträchtliche Schäden verursachen

Comparison of the Nutritive Quality of Tomato Fruits from Organic and Conventional Production in Poland

Organic horticulture is generally accepted as friendly to the environment, good for crop quality and also for the consumer’s health. Recent research data has shown that organic crops under organic farming practices contained more bioactive substances such as flavones, vitamin C, carotenoids; they also contain less pesticides residues, nitrates and nitrites. Five tomato cultivars: four large – fruit (Rumba, Juhas, Kmicic, Gigant) and one cherry cultivar (Koralik) were selected for study. The organic tomato fruits contained more dry matter, total and reducing sugars, vitamin C, total flavones and beta-carotene, but less lycopene in comparison to conventionally grown tomatoes

Influence of Processing on Bioactive Substances Content and Antioxidant Properties of Apple Purée from Organic and Conventional Production in Poland

The organic food market is developing dynamically in many European countries and therefore studies concerning the nutritive value of organically produced foods are becoming increasingly important. It was found appropriate to conduct studies on selected bioactive substances and antioxidant properties of apple preserves prepared from organic vs. conventional apples. Three apple cultivars, Lobo, Boskoop and Cortland, were grown in organic and conventional orchards in the Mazovia region in Poland. Dry matter, total phenols, vitamin C, total flavones and antioxidant activity were determined in fresh and pasteurized apple purée. The apple purée prepared from the organic apples contained significantly more total phenols, vitamin C, total flavones and showed a higher antioxidant capacity than the preserves prepared from conventional apples. Processing had a negative effect on both antioxidant capacity and bioactive substances. After pasteurization, the content of vitamin C, total phenols and flavones and antioxidant properties have decreased in the apple purée from both agricultural systems (organic and conventional)

Nest predation in Afrotropical forest fragments shaped by inverse edge effects, timing of nest initiation and vegetation structure

High levels of nest predation influence the population dynamics of many tropical birds, especially when deforestation alters nest predator communities. The consequences of tropical forest fragmentation on nest predation, however, remain poorly understood, as natural predation patterns have only been well documented in a handful of tropical forests. Here, we show the results of an extensive study of predation on natural nests of Cabanis's Greenbul (Phyllastrephus cabanisi) during 3 years in a highly fragmented cloud forest in SE Kenya. Overall predation rates derived from 228 scrub nests averaged 69 %, matching the typical high predation level on tropical bird species. However, predation rates strongly varied in space and time, and a model that combined timing effects of fragment, edge, concealment, year and nest was best supported by our data. Nest predation rates consistently increased from forest edge to interior, opposing the classic edge effect on nest predation, and supporting the idea that classic edge effects are much rarer in Afrotropical forests than elsewhere. Nest concealment also affected predation rates, but the strength and direction of the relationship varied across breeding seasons and fragments. Apart from spatial variation, predation rates declined during the breeding season, although the strength of this pattern varied among breeding seasons. Complex and variable relationships with nest predation, such as those demonstrated here, suggest that several underlying mechanisms interact and imply that fixed nesting strategies may have variable-even opposing-fitness effects between years, sites and habitats

Beiträge zu Problemen der Erstauftreffzeiten der Brownschen Bewegung

Let W be a standard Brownian motion with W(0) = 0 and let b be a continuous function with b(0) > 0. The first passage time of b (from below) is then defined as the first time W crosses b (from below). A well-known method to determine the distribution of is the method of images. It gives an explicit expression for the the first hitting time distribution for all boundaries b that are the implicit solution to an integral equation which depends on some measure μ. However, the boundary b cannot be determined explicitly for most choices of μ. Therefore, the inverse method of images has emerged – at least as a numerical approach – to determine the measure μ and thus the distribution of for a given boundary b. If a measure μ exists, the boundary b will be called representable. Until now, it remained an open question for which boundaries b a measure μ exists such that b is representable. In this thesis, we present a new duality approach to the inverse method of images which enables us to give sufficient conditions for the existence of representing measures μ for concave, analytic boundaries b. Based on that, we put forward a new algorithm that improves upon existing algorithms for the inverse method of images by requiring less discretisations and giving precise approximations with very fast convergence. We also give convergence guarantees for this algorithm. As an application, we establish a connection between the existence of first passage time distributions and the representability of American options via European options. This thesis concludes by approaching the first passage time problem via Fredholm type integral equations for which we show that these uniquely determine the distribution of the first passage time

Untersuchung möglicher Faktoren von nesterweise auftretenden Wuchsdepressionen bei Getreide auf Ökobetrieben mit leichten Böden

Evaluating the problem of spotwise appearing cereal growth depressions 23 fields of 10 organic managed farms were investigated. Potential causes were soil nutrients and other chemical and physical soil properties as well as high abundance of the plant parasitic nematodes Heterodera avenae and Pratylenchus-, Tylenchorhynchus and Trichodorus species. In two on-farm field experiments different catch crops and a black fallow treatment caused a decrease of Pratylenchus and Tylenchorhynchus species. However, the yields of the following spring wheat were low, possibly due to H. avenae infestation. Fertilization with compost and potassium had no effect but the H. avenae resistant variety Isotta produced much higher yields. The conclusion drawn was that farmers with spotwise appearing growth depressions should watch them closely for nematode infestation to take regulation measures as early as possible

Kevin Laird Hallmann in a Senior Piano Composition Recital

This is the program for the senior piano composition recital of Kevin Laird Hallmann. This recital took place on April 14, 1988, in the Mabee Fine Arts Recital Hall

Kevin Laird Hallmann in a Junior Piano Recital

This is the program for the junior piano recital of Kevin Laird Hallmann. The recital took place on January 26, 1987, in the Mabee Fine Arts Recital Hall

Nachhaltige Wirkung von Ölrettich auf die Abundanzdynamik von Wurzelgallennematoden im ökologischen Landbau

Der Wurzelgallennematode Meloidogyne hapla ist einer der bedeutendsten Schaderreger im ökologischen Landbau. Direkte Bekämpfungsmaßnahmen oder resistente Sorten stehen nicht zur Verfügung, so dass eine Bekämpfung derzeit nur über die Fruchtfolge möglich ist. Während im Vorläufer-Projekt (02OE107) die Einsatzmöglichkeiten von Ölrettich (Raphanus sativus) als Zwischenfrucht bzw. Fangpflanze zur Bekämpfung von M. hapla aufgezeigt wurden, sollte in dem vorliegenden Forschungsvorhaben die Wirksamkeit dieser Maßnahmen auf den Ertrag von Kartoffeln als Folgekultur untersucht werden. Da neben M. hapla auf den Versuchsflächen zusätzlich Pratylenchus spp. auftrat, wurde diese Nematodengattung bei den Untersuchungen mit berücksichtigt. Unter den Anbaubedingungen des Jahres 2004 kam es zu keiner Vermehrung von M. hapla an Kartoffeln, obwohl Klimabedingungen und Kulturdauer grundsätzlich förderlich waren. Möglicherweise liegt hier ein ausgeprägte Sortenabhängigkeit gegenüber M. hapla zugrunde und 'Linda' bzw. 'Solara' zählen zu den wenig anfälligen Sorten. Im Gegensatz zu M. hapla konnte sich Pratylenchus spp. an beiden Kartoffelsorten gut entwickeln. Die Vermehrungsraten lagen zwischen 2,3 und 8,4. Im Kartoffelertrag zeigten sich auf beiden Versuchsflächen keine Unterschiede in Abhängigkeit der Vorkultur. Andere Faktoren, wie z. B. die Nährstoffwirkung der Vorfrucht, haben eine mögliche Schädigung durch pflanzenparasitäre Nematoden vermutlich überlagert. Die Untersuchungen haben aber auch gezeigt, dass die Ölrettichsorte 'Commodore' den Wurzelgallennematoden M. hapla signifikant weniger vermehrt als die Ölrettichsorte 'Siletina', so dass 'Commodore' auf Befallsflächen bevorzugt angebaut werden sollte. Den besten Bekämpfungserfolg von M. hapla hatte die Brache. Dies ist aber wenig ökologisch, so dass geeignete Alternativen zu entwickeln sind. Eine Alternative ist der Anbau von Ölrettich als Fangpflanze. In dem vorliegenden Forschungsvorhaben wurde der Ölrettich in 2003 allerdings zu spät umgebrochen und zeigte keine optimale Wirkung. Innerhalb weiterführender Untersuchungen in 2004 konnten jedoch Bekämpfungsraten bis zu 97 % erzielt werden, was das grundsätzliche Funktionieren dieses Verfahrens hervorhebt