860 research outputs found
The sustainable future of implementation research: On the development of the field and its paradoxes
__Abstract__
As fashionable as implementation studies were in the 1970s and 1980s, as en vogue it has become four decades later to consider implementation as a research theme of the past. It is clear that in the study of government new themes and concepts have been put on the agenda. In the ‘age of governance’ that study takes place under a variety of headings beyond ‘implementation’. At the same time a continued attention to what happens with policies-on-paper can be observed. In this special issue the development of implementation research as a scholarly field is assessed. A closer look reveals some paradoxes, but also steady advancement
Eignung verschiedener Körnerleguminosen als Vorfrucht für Winterweizen in ökologischen Fruchtfolgen
The Aim of this study has been to evaluate in two two-year field trials the pre-crop effect of different grain legumes (e.g. soy bean, peas or lupines) in the same environment and to detect possible effects of grain legumes on the N-supply, the yield potential and the yield structure of the subsequent crop winter wheat. According to different pre-crop yields, a higher but different nitrogen supply for subsequent winter wheat was observed in all N2-fixing pre-crop treatments. In contrast to non-fixings control higher NO3-N contents in soil and higher yields in subsequent winter wheat (up to 24 dt*ha- 1 surplus) were observed
Optimierte Bestimmung der unterirdischen Pflanzenbiomasse in Theorie und Praxis
Will man den C oder N Eintrag von Pflanzen ermitteln, muss die unterirdische Pflanzenbiomasse möglichst exakt bestimmt werden. Diese besteht aus der Rhizodeposition und dem Wurzelsystem einer Pflanze. Als Rhizodeposition wird die Abgabe von organischen und anorganischen Verbindungen bezeichnet. Sie setzt sich unter anderem aus Wurzelfragmenten, Wurzelrandzellen, Wurzelexudaten und Lysaten zusammen.
Auf Grund einer fehlenden Wurzelraumbegrenzung, ist die Erfassung des vollständigen Wurzelsystems einer Pflanze im Freiland problematisch. Zur Quantifizierung von Wurzelsystemen sind jedoch Freilandversuche stets Gefäßversuchen vorzuziehen, da nur so ein ungestörtes Wurzelwachstum erreicht werden kann. Als Konsequenz lassen sich unterschiedliche Wurzel-Spross-Verhältnisse in Gefäß- und Freilandversuchen feststellen. Verlagerungsprozesse innerhalb der Pflanze können zusätzlich die Berechnung der Rhizodeposition beeinflussen und so zur Über- oder Unterschätzung der unterirdischen Pflanzenbiomasse führen. Ziel war daher ein Beprobungsschema zu entwickeln, welches es ermöglicht die Wurzelbiomasse im Freiland zu erfassen und unterschiedliche Berechnungsmethoden der Rhizodeposition zu vergleichen.
Hierfür wurden sowohl im Gefäß als auch im Freiland Erbsen mittels Dochtmethode mit multiplen 13C und 15N-Pulsen markiert, wodurch eine annähernd kontinuierliche Markierung simuliert wurde. Die Wurzelbiomasse der Erbse wurde im Freiland bestimmt, indem Unterproben mit einem definierten Volumen in 3 festgelegten Positionen im Bestand genommen wurden (direkt auf einer Pflanze; zwischen 2 Pflanzen in der Reihe; in der Mitte von 4 Pflanzen zwischen 2 Reihen). Durch die unterschiedliche Gewichtung der Positionen, die sich aus dem Beprobungsdurchmesser und dem Pflanze-/Reihenabstand ergaben, konnte die vollständige Wurzelbiomasse bestimmt werden. Die Rhizodeposition wurde mit einer Massenbilanz (1) und mit der Janzen und Bruinsma Methode (2) ermittelt.
Zum Zeitpunkt der Blüte waren die Wurzelbiomasse und das Wurzel-Spross-Verhältnis im Feld um ein vielfaches Größer verglichen mit dem Gefäß. Bei der Berechnung nach Janzen und Bruinsma können Verlagerungsprozesse während der Blüte zur Überschätzung der Rhizodeposition führen. Erfolgt eine kontinuierliche Markierung über den gesamten Vegetationsverlauf, so kann die Rhizodeposition am Kulturende sowohl nach Janzen und Bruinsma als auch mit der Massenbilanz berechnet werden
Antarctic Surface Reflectivity Measurements from the ANITA-3 and HiCal-1 Experiments
The primary science goal of the NASA-sponsored ANITA project is measurement
of ultra-high energy neutrinos and cosmic rays, observed via radio-frequency
signals resulting from a neutrino- or cosmic ray- interaction with terrestrial
matter (atmospheric or ice molecules, e.g.). Accurate inference of the energies
of these cosmic rays requires understanding the transmission/reflection of
radio wave signals across the ice-air boundary. Satellite-based measurements of
Antarctic surface reflectivity, using a co-located transmitter and receiver,
have been performed more-or-less continuously for the last few decades.
Satellite-based reflectivity surveys, at frequencies ranging from 2--45 GHz and
at near-normal incidence, yield generally consistent reflectivity maps across
Antarctica. Using the Sun as an RF source, and the ANITA-3 balloon borne
radio-frequency antenna array as the RF receiver, we have also measured the
surface reflectivity over the interval 200-1000 MHz, at elevation angles of
12-30 degrees, finding agreement with the Fresnel equations within systematic
errors. To probe low incidence angles, inaccessible to the Antarctic Solar
technique and not probed by previous satellite surveys, a novel experimental
approach ("HiCal-1") was devised. Unlike previous measurements, HiCal-ANITA
constitute a bi-static transmitter-receiver pair separated by hundreds of
kilometers. Data taken with HiCal, between 200--600 MHz shows a significant
departure from the Fresnel equations, constant with frequency over that band,
with the deficit increasing with obliquity of incidence, which we attribute to
the combined effects of possible surface roughness, surface grain effects,
radar clutter and/or shadowing of the reflection zone due to Earth curvature
effects.Comment: updated to match publication versio
Doing implementation research on health governance: a frontline researcher’s reflexive account of field-level challenges and their management
BACKGROUND: Implementation Research (IR) in and around health systems comes with unique challenges for
researchers including implementation, multi-layer governance, and ethical issues. Partnerships between
researchers, implementers, policy makers and community members are central to IR and come with
additional challenges. In this paper, we elaborate on the challenges faced by frontline field researchers,
drawing from experience with an IR study on Village Health Sanitation and Nutrition Committees (VHSNCs).
METHODS: The IR on VHSNC took place in one state/province in India over an 18-month research period.
The IR study had twin components; intervention and in-depth research. The intervention sought to
strengthen the VHSNC functioning, and concurrently the research arm sought to understand the contextual
factors, pathways and mechanism affecting VHSNC functions. Frontline researchers were employed for data
collection and a research assistant was living in the study sites. The frontline research assistant experienced
a range of challenges, while collecting data from the study sites, which were documented as field memos
and analysed using inductive content analysis approach.
RESULTS: Due to the relational nature of IR, the challenges coalesced around two sets of relationships (a)
between the community and frontline researchers and (b) between implementers and frontline researchers.
In the community, the frontline researcher was viewed as the supervisor of the intervention and was
perceived by the community to have power to bring about beneficial changes with public services and
facilities. Implementers expected help from the frontline researcher in problem-solving in VHSNCs, and
feedback on community mobilization to improve their approaches. A concerted effort was undertaken by
the whole research team to clarify and dispel concerns among the community and implementers through
careful and constant communication. The strategies employed were both managerial, relational and
reflexive in nature.
CONCLUSION: Frontline researchers through their experiences shape the research process and its outcome
and they play a central role in the research. It demonstrates that frontline researcher resilience is very
crucial when conducting health policy and systems research.Scopu
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