The Relationships Among Rapid Automatized Naming (RAN), Processing Speed and Reading Fluency in Clinic Referred Children

Converging evidence suggests that phonological awareness is at the core of reading ability. Rapid automatized naming (RAN), defined as how quickly individuals can name continuously presented familiar visual stimuli, is also known to be a strong predictor of reading performance, and reading fluency in particular. The double deficit hypothesis suggests RAN deficits represent an additional core deficit associated with the reading process. Although there are many ways to measure RAN (e.g., using letters, numbers, pictures, objects), not well established is which RAN task is most predictive of the reading fluency skills of clinic referred children. Further research is also needed to understand the relationship between RAN and general processing speed, and the extent to which RAN tasks uniquely predict the reading fluency of clinic-referred children. The purpose of the current study is to determine a) the relationships among phonemic awareness, RAN, general processing speed, and reading fluency; b) the predictive value of phonemic awareness and RAN tasks in determining reading fluency performance; c) which RAN task best predicts reading fluency; and d) if RAN tasks continue to predict reading fluency while controlling for general processing speed. 64 children from a university reading clinic were used as participants in this study. The results suggest that alphanumeric RAN task performance --and letter naming in particular-- are unique contributors to reading fluency performance in dysfluent readers. Further, the results indicate that this contribution to reading fluency extends beyond that of other theoretical components of fluency

Direkte und indirekte Effekte von eingeschleppten Parasiten auf heimische Miesmuscheln

The role of parasites in invasion processes have become an increasing phenomenon due to the continuous increase in the rate of biological invasions in marine ecosystems. When parasites themselves are invasive and spill over to native species, they can exert a number of direct and indirect effects on their new host and interacting species. Direct effects often affect the new host in multiple ways that result in further indirect effects downstream. Moreover, the occurrence of indirect effects might change the interaction of the host to interacting species. As a result of both, direct and indirect effects, parasites can change the sensitivity of the host against further impacts like climate change and/or secondary infections. This can have profound ecological consequences for native biota. In combination, the challenges of invasion processes and climate change bear the risk of species homogenization and disease emergence. Against this background, it is an urgent task of marine science to assess future impacts and consequences of parasite invasions and climate change. The present study investigates the direct and indirect effects of the invasive parasite Mytilicola intestinalis on native blue mussels. The study is divided into three chapters; the first chapter addresses the direct effects, while the second and third chapter considers indirect effects.Mit der Zunahme biologischer Invasionen innerhalb des marinen Ökosystems wächst die Rolle von Parasiten in solchen Invasionsprozessen stetig. Wenn Parasiten selbst invasiv sind und auf heimische Arten überwechseln, können sie eine Reihe direkter und indirekter Effekte auf den neuen Wirt und die mit ihm interagierenden Arten ausüben. Direkte Effekte wirken auf vielfältige Weise auf den Wirt ein, daraus können wiederum indirekte Effekte hervorgehen. Indirekte Effekte können weiter auf die Interaktion zwischen Wirten und die mit ihnen wechselwirkenden Arten einwirken. Als Folge von beidem (direkten und indirekten Effekten) können Parasiten die Sensibilität eines Wirtes gegenüber weiteren Einflüssen, wie beispielsweise veränderten Klimabedingungen und/oder Sekundärinfektionen, beeinflussen. Dies hat tiefgreifende ökologische Auswirkungen für heimische Arten. Insgesamt bergen die Herausforderungen von Invasionsprozessen und dem Klimawandel das Risiko der Artenhomogenisierung und dem Aufkommen von Krankheiten. Vor diesem Hintergrund ist es eine der Hauptaufgaben der marinen Forschung zukünftige Einflüsse und Folgen von parasiten-beeinflussten Invasionen und dem Klimawandel abzuschätzen. In der vorliegenden Arbeit werden die direkten und indirekten Effekte des invasiven Parasiten Mytilicola intestinalis auf heimische Miesmuscheln untersucht. Die Arbeit gliedert sich in drei Kapitel, das erste Kapitel befasst sich mit den direkten Effekten, Kapitel zwei und drei mit den indirekten Effekten

First report on Pythium myriotylum as pathogen on duckweed (Lemna minor L.) in hydroponic systems in Germany

Wasserlinsen sind eine vielversprechende Ressource für die zukünftige Produktion von Futter- und Nahrungsmitteln sowie die Abwasserreinigung. Krankheiten und Schädlinge können die Leistung der Produktionssysteme jedoch kritisch einschränken. In hydroponischen Systemen traten Flecken missfarbiger und gebleichter Wasserlinsen (Lemna minor L.) auf, die sich rasch im Bestand ausbreiteten. Durch mikrobiologische und molekularbiologische Untersuchungen wurde Pythium myriotylum als ursächlicher Schaderreger eindeutig nachgewiesen. Dies ist der erste Bericht über P. myriotylum an Wasserlinsen in Deutschland. Das Ergebnis und mögliche Gegenmaßnahmen werden erörtert.Duckweed is a promising resource for future feed and food production as well as wastewater treatment. However, diseases and pests can critically limit the performance of the production systems. Patches of discolored and bleached duckweed (Lemna minor L.) appeared in hydroponic systems and spread rapidly through the crop. Pythium myriotylum was confirmed as the causing pathogen by microbiological and molecular biological analysis. This is the first report of P. myriotylum on duckweed in Germany. The result and possible countermeasures are discussed

Invading the Occupied Niche: How a Parasitic Copepod of Introduced Oysters Can Expel a Congener From Native Mussels

In species introductions, non-native species are often confronted with new niches occupied by more specialized natives, and for introduced parasites this conflict can be amplified because they also face novel hosts. Despite these obstacles, invasions of introduced parasites occur frequently, but the mechanisms that facilitate parasite invasion success are only rarely explored. Here, we investigated how the parasitic copepod Mytilicola orientalis, that recently spilled over from its principal host - the Pacific oyster Crassostrea gigas, managed to invade the niche of blue mussel Mytilus edulis intestines, which is densely occupied by its specialist congener, Mytilicola intestinalis. From field observations demonstrating invasion dynamics in nature, we designed a series of experiments addressing potential mechanisms facilitating a successful occupation of the new niche. As expected the specialist M. intestinalis can only infect mussel hosts, but displayed higher infection success there than M. orientalis in both principal host species combined. In the absence of direct competitive interactions M. orientalis compensated its lower infection success (1) by recurrent spill-over from its high-fitness reservoir oyster host, and (2) by active aggregation interference enhancing its own mating success while limiting that of M. intestinalis. The introduced parasite could thus avoid direct competition by changing its own epidemiology and indirectly decreasing the reproductive success of its competitor in the new host. Such mechanisms outside of direct competition have seldom been considered, but are crucial to understand invasion success, parasite host range and community assembly in the context of species introductions

Design of an unmanned Martian polar exploration system

The design of an unmanned Martian polar exploration system is presented. The system elements include subsystems for transportation of material from earth to Mars, study of the Martian north pole, power generation, and communications. Early next century, three Atlas 2AS launch vehicles will be used to insert three Earth-Mars transfer vehicles, or buses, into a low-energy transfer orbit. Capture at Mars will be accomplished by aerobraking into a circular orbit. Each bus contains four landers and a communications satellite. Six of the twelve total landers will be deployed at 60 deg intervals along 80 deg N, and the remaining six landers at 5 deg intervals along 30 deg E from 65 deg N to 90 deg N by a combination of retrorockets and parachutes. The three communications satellites will be deployed at altitudes of 500 km in circular polar orbits that are 120 deg out of phase. These placements maximize the polar coverage of the science and communications subsystems. Each lander contains scientific equipment, two microrovers, power supplies, communications equipment, and a science computer. The lander scientific equipment includes a microweather station, seismometer, thermal probe, x-ray spectrometer, camera, and sounding rockets. One rover, designed for short-range (less than 2 km) excursions from the lander, includes a mass spectrometer for mineral analysis, an auger/borescope system for depth profiling, a deployable thermal probe, and charge coupled device cameras for terrain visualization/navigation. The second rover, designed for longer-range (2-5 km) excursions from the lander, includes radar sounding/mapping equipment, a seismometer, and laser ranging devices. Power for all subsystems is supplied by a combination of solar cells, Ni-H batteries, and radioisotope thermoelectric generators. Communications are sequenced from rovers, sounding rockets, and remote sensors to the lander, then to the satellites, through the Deep Space Network to and from earth

The Threat of Capital Drain: A Rationale for Public Banks?

This paper yields a rationale for why subsidized public banks may be desirable from a regional perspective in a financially integrated economy. We present a model with credit rationing and heterogeneous regions in which public banks prevent a capital drain from poorer to richer regions by subsidizing local depositors, for example, through a public guarantee. Under some conditions, cooperative banks can perform the same function without any subsidization; however, they may be crowded out by public banks. We also discuss the impact of the political structure on the emergence of public banks in a political-economy setting and the role of interregional mobility

Reform of Unemployment Compensation in Germany : A Nonparametric Bounds Analysis Using Register Data

Economic theory suggests that an extension of the maximum length of entitlement for unemployment benefits increases the duration of unemployment. Empirical results for the reform of the unemployment compensation system in Germany during the 1980s are less clear. The analysis in this paper is motivated by the controversial empirical findings and by recent developments in econometrics for partial identification. We use extensive administrative data with the drawback that registered unemployment is not directly observed. For this reason we bound the reform effect on unemployment duration over different definitions of unemployment. By exploiting the richness of the data we use a nonparametric approach without imposing critical parametric model assumptions. We identify a systematic increase in unemployment duration in response to the reform in samples that amount to less than 15% of the unemployment spells for the treatment group

Increased Instruction Hours and the Widening Gap in Student Performance

Do increased instruction hours improve the performance of all students? Using PISA scores of students in ninth grade, we analyse the effect of a German education reform that increased weekly instruction hours by two hours (6.5 percent) overalmost five years. In the additional time, students are taught new learning content. On average, the reform improves student performance. However, treatment effects are small and differ across the student performance distribution. While low-performing students do not benefit, high-performing students benefit the most. The findings suggest that increases in instruction hours can widen the gap between low- and high-performing students