Contrasting effects of hemiparasites on ecosystem processes: can positive litter effects offset the negative effects of parasitism?

Hemiparasites are known to influence community structure and ecosystem functioning, but the underlying mechanisms are not well studied. Variation in the impacts of hemiparasites on diversity and production could be due to the difference in the relative strength of two interacting pathways: direct negative effects of parasitism and positive effects on N availability via litter. Strong effects of parasitism should result in substantial changes in diversity and declines in productivity. Conversely, strong litter effects should result in minor changes in diversity and increased productivity. We conducted field-based surveys to determine the association of Castillejaoccidentalis with diversity and productivity in the alpine tundra. To examine litter effects, we compared the decomposition of Castilleja litter with litter of four other abundant plant species, and examined the decomposition of those four species when mixed with Castilleja. Castilleja was associated with minor changes in diversity but almost a twofold increase in productivity and greater foliar N in co-occurring species. Our decomposition trials suggest litter effects are due to both the rapid N loss of Castilleja litter and the effects of mixing Castilleja litter with co-occurring species. Castilleja produces litter that accelerates decomposition in the alpine tundra, which could accelerate the slow N cycle and boost productivity. We speculate that these positive effects of litter outweigh the effects of parasitism in nutrient-poor systems with long-lived hemiparasites. Determining the relative importance of parasitism and litter effects of this functional group is crucial to understand the strong but variable roles hemiparasites play in affecting community structure and ecosystem processes

Die Entwicklung und Implementierung einer mobilen kontext-sensitiven Anwendung zur Bildung einer Rettungsgasse

Tragische Unfälle auf Autobahnen, bei denen keine Rettungsgasse gebildet wird oder Rettungsgassen missbräuchlich benutzt werden, kursieren immer wieder in den Medien. Oft wissen die Verkehrsteilnehmer nicht wann und, gerade bei mehr als zwei Spuren, wie eine Rettungsgasse zu bilden ist. Dabei kommt es bei schweren Unfällen auf jede Minute oder gar Sekunde an. Um die Bekanntheit und die richtige Bildung einer Rettungsgasse zu unterstützen, ist eine mobile Anwendung an der Hochschule Landshut in Zusammenarbeit mit dem bayerischen Innenministerium und dem ADAC e.V. entwickelt worden. Sie kann den Kontext des Benutzers erfassen und im Ernstfall einen akustischen und visuellen Warnhinweis ausgeben. Zudem unterstützt eine schematische Grafik einer Rettungsgasse auf dem Smartphone-Display bei der Bildung einer Rettungsgasse

Vergleichende Analyse von Open‐Source‐Modellierungswerkzeugen als Basis für Forschungsprototypen

In der Wirtschaftsinformatik lassen sich zwei Grundtypen von Forschungsfragen unterscheiden. Zum einen existieren Forschungsfragen, die den aktuellen Einsatz, die Entwicklung oder das Controlling von Informationssystemen untersuchen. Diese dem Behaviorismus zuzuordnen Forschungsfragen zielen darauf ab, den aktuellen State-of-the-Art zu erheben. Zum anderen werden insbesondere in der deutschsprachigen Wirtschaftsinformatik Forschungsfragen untersucht, die darauf abzielen im Sinne eines ingenieurmäßigen Vorgehens neue Methoden, Softwarewerkzeuge oder Informationssysteme zu entwickeln. Diese Gruppe von Forschungsfragen lässt sich dem Design-Science-Paradigma zuordnen. Ein Kerngebiet der Wirtschaftsinformatik, das insbesondere den Bau von Prototypen erfordert, sind Arbeiten die sich dem Themenfeld der Informationsmodellierung zuordnen lassen. Falls für ein Forschungsvorhaben also feststeht, dass sich dem Design-Science-Paradigma zurechnen lässt und es sich unter das Themenfeld der Informationsmodellierung subsumieren lässt, ist oft der Bau eines Prototypen als Demonstrators Teil der Forschungsagenda. Um Aufwand zu sparen bietet sich die Erweiterung eines bestehenden Open-Source-Modellierungswerkzeuges an. Das Gesamtziel des Betrages besteht darin die Selektion des geeigneten Open-Source-Modellierungswerkzeuges für den Bau eigener Forschungsprototypen zu erleichtern

Disorders of consciousness after acquired brain injury: the state of the science

The concept of consciousness continues to defy definition and elude the grasp of philosophical and scientific efforts to formulate a testable construct that maps to human experience. Severe acquired brain injury results in the dissolution of consciousness, providing a natural model from which key insights about consciousness may be drawn. In the clinical setting, neurologists and neurorehabilitation specialists are called on to discern the level of consciousness in patients who are unable to communicate through word or gesture, and to project outcomes and recommend approaches to treatment. Standards of care are not available to guide clinical decision-making for this population, often leading to inconsistent, inaccurate and inappropriate care. In this Review, we describe the state of the science with regard to clinical management of patients with prolonged disorders of consciousness. We review consciousness-altering pathophysiological mechanisms, specific clinical syndromes, and novel diagnostic and prognostic applications of advanced neuroimaging and electrophysiological procedures. We conclude with a provocative discussion of bioethical and medicolegal issues that are unique to this population and have a profound impact on care, as well as raising questions of broad societal interest

Waiting times for radiotherapy: variation over time and between cancer networks in southeast England

The aim of this study was to investigate variations in the length of time that patients with cancer wait from diagnosis to treatment with radiotherapy. A total of 57426 men and 71018 women diagnosed with cancer between 1992 and 2001 and receiving radiotherapy within 6 months of diagnosis were identified from the Thames Cancer Registry database. In total, 12 sites were identified for which a substantial number or proportion of patients received radiotherapy: head and neck, oesophagus, colon, rectum, lung, nonmelanoma skin cancer, breast, uterus, prostate, bladder, brain and non-Hodgkin's lymphoma. Median waiting times from diagnosis to radiotherapy were calculated, together with the proportion of patients who received radiotherapy within 60 days of diagnosis, and analysed by year of diagnosis, cancer site, deprivation quintile, age at diagnosis, sex and cancer network of either residence or treatment. Logistic regression was used to adjust the proportion receiving treatment within 60 days for the effects of the other factors. There were significant differences in the proportions receiving radiotherapy within 60 days between different networks and different cancer sites, which remained after adjustment. Median waiting times varied from 42 to 65 days across networks of residence, with the adjusted proportion treated within 60 days ranging from 44 to 71%. There was no difference between male and female patients after adjustment for the other factors, particularly site. There was a highly significant trend over time: the median wait increased from 45 days in 1992 to 76 days in 2001, while the adjusted proportion being treated within 60 days declined by almost a half, from 64 to 35%, over the same period. © 2005 Cancer Research UK