3,247 research outputs found

    Green light for gene targeting in plants

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    Annual and Season Weight Changes in a Thirteen-Lined Ground Squirrel Population, Itasca State Park, Minnesota

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    The ecology of the thirteen-lined ground squirrel (Citellus tridecemlineotus) has been under investigation since 1954 on the grounds of the University of Minnesota Forestry and Biological Station located in Itasca State Park, Minnesota. Over the 11-year period, data have been collected on individuals of this small, relatively isolated, population. Studies of population dynamics, movements, activity patterns, and weights have been stressed, chiefly during the three summer months of June, July, and August. In 1964, the senior author carried out field work for the entire season from April 30 to September 14

    Amphicarpic Legumes for Tropical Pasture Persistence

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    Amphicarpy, by which a plant produces underground seeds in addition to aerial fruits, is found in many plant families and in species of at least 15 legume genera. First studies on the tropical Centrosema rotundifolium and subtropical Macroptilium panduratum revealed for both species, besides their stoloniferous growth habit, two important mechanisms for survival under unfavorable conditions: (1) Underground meristems and reserve organs, and (2) regeneration from a soil seed reserve based on underground, aerial-flowering independent, seed production. Underground seed production was for both species particularly high on very sandy soils, but amphicarpy enables the plants to exhibit a plasticity response to unfavourable soil conditions by changing resource allocation from underground to above-ground reproduction. The latter, which seems to be influenced by cross-pollination and thus aids gene-recombination, favours spreading of plant populations whereas underground reproduction ensures population survival on-site. Preliminary information on the agronomic potential of both species is given and several research needs are highlighted

    Forschungspolitik als Ordnungspolitik: Das Modell Fraunhofer-Gesellschaft und seine Genese im Forschungssystem der Bundesrepublik Deutschland

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    Das Papier untersucht die Genese und Institutionalisierung der Fraunhofer-Gesellschaft als Organisation fĂŒr die Vertragsforschung im außeruniversitĂ€ren Forschungssystem der Bundesrepublik. In der Folge interorganisatorischer DomĂ€nenkonf likte wurde die Gesellschaft in der Mitte der fĂŒnfziger Jahre zunĂ€chst aus der Forschungsfinanzierung des Bundes ausgeschlossen. Im Interesse ihrer Überlebenssicherung nutzte sie die Gelegenheit, mit UnterstĂŒtzung vor allem durch das Land Baden-WĂŒrttemberg in der industriellen Vertragsforschung tĂ€tig zu werden, drohte mit diesem Konzept aber an Schwellenproblemen zu scheitern. MilitĂ€rische Forschungsmittel ermöglichten es der Gesellschaft, diese Schwellenprobleme zu ĂŒberwinden und ein moderates, aber stabiles Wachstum der zivilen Vertragsforschung herbeizufĂŒhren. An diese Entwicklung knĂŒpfte die Reform der Gesellschaft durch die Bundesregierung und ihr Ausbau zur TrĂ€gerorganisation in der angewandten Forschung am Anfang der siebziger Jahre lediglich an. Das "Modell Fraunhofer-Gesellschaft" beruht auf institutionellen Strukturen, die sich in einem Prozeß von situativ ineinandergreifenden Verkettungen und einer daraus resultierenden pfad-abhĂ€ngigen Wachstumsdynamik der Vertragsforschung herausgebildet haben.This paper examines the genesis and institutionalization of the Fraunhofer-Gesellschaft (FhG) as an organization for contract-research in the West-German research system outside the universities. As a result of interorganizational conf licts of domain in the midf ifties, the FhG was for the time being excluded from state-funding. The society survived by taking the chance of conducting contract-research subsidized mainly by Baden-WĂŒrttemberg. The concept of contractresearch, however, was on the brink of failure due to threshold-problems. Military research funds made it possible for the FhG to cross these threshold-problems and to induce a moderate but stable growth of civilian contract-research. The reformation of the society by the federal government and its extension to the mainly responsible institution in the field of applied research during the early seventies only picked up this development. The "Modell Fraunhofer-Gesellschaft" is based on institutional structures which emerged in a process of situative "lock-ins" leading to a pathdependend increase of contract-research.Vorbemerkung Verzeichnis der AbkĂŒrzungen 1 Vom "Lumpensammler" zum Forschungskonzern. Das RĂ€tsel der zwei Fraunhofer-Gesellschaften 2 Der kurze Aufstieg und rasche Niedergang der Fraunhofer-Gesellschaft als "komplementĂ€re" Forschungsorganisation am Beginn der fĂŒnfziger Jahre 2.1 GrĂŒndungsabsicht und Zielverschiebung. Von der bayerischen Landeseinrichtung zur dritten "SĂ€ule" des bundesdeutschen Forschungssystems 2.2 Das Königsteiner Abkommen und der DomĂ€nenkonflikt mit der Deutschen Forschungsgemeinschaft und der Max-Planck-Gesellschaft 2.3 Bruch mit dem Stifterverband und dem Bundesministerium fĂŒr Wirtschaft. Der vorlĂ€ufige Ausschluß der FhG aus der Forschungsförderung des Bundes 3 Vertragsforschung als Nischenstrategie. Das forschungspolitische Konzept der sĂŒdwestlichen LĂ€nder und der Beitrag der militĂ€rischen Forschung zum "Modell Fraunhofer-Gesellschaft" 3.1 Forschungspolitik im Dienst der Industriepolitik. Das Interesse Baden-WĂŒrttembergs an der Vertragsforschung und die neue IdentitĂ€t der FhG 3.2 Der Teufelskreis von fehlenden Mitteln fĂŒr die Eigenforschung und ausbleibenden ErtrĂ€gen aus der Vertragsforschung 3.3 MilitĂ€rische Forschung als Eigenforschung. Auswege aus dem Dilemma 3. 3 .1 Der Abbau des Juliusturms und die Isolation der militĂ€rischen Forschung 3.3.2 Die Funktion militĂ€rischer Projektmittel fĂŒr das organisatorische Wachstum der FhG 3. 4 Dezentrale Akquisition und zentrale Mittelverteilung. Organisatorische Strukturmerkmale der FhG als Folge chronisch knapper Mittel fĂŒr die Eigenforschung 4 Vom Kompetenzstreit zwischen Bund und LĂ€ndern zur ordnungspolitischen Aufteilung des Forschungssystems 4.1 Das Autonomiebestreben der großen Forschungsorganisationen und die Rolle der angewandten Forschung in der DFG 4.2 Das neue Interesse an einer "dritten SĂ€ule" des bundesdeutschen Forschungssystems nach dem Verwaltungsabkommen von 1964 4. 3 Von der Förderung der industriellen Forschung als "Ausnahmefall" zur Technologiepolitik des Bundes 5 Retrospektive Sinngebung und Ordnungspolitik. Die Funktion der Strukturreform am Beginn der siebziger Jahr

    Stochastic Voronoi Tessellations as Models for Cellular Neighborhoods in Simple Multicellular Organisms

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    Recent work on distinct multicellular organisms has revealed a hitherto unknown type of biological noise; rather than a regular arrangement, cellular neighborhood volumes, obtained by Voronoi tessellations of the cell locations, are broadly distributed and consistent with gamma distributions. We propose an explanation for those observations in the case of the alga VolvoxVolvox, whose somatic cells are embedded in an extracellular matrix (ECM) they export. Both a solvable one-dimensional model of ECM growth derived from bursty transcriptional activity and a two-dimensional "Voronoi liquid" model are shown to provide one-parameter families that smoothly interpolate between the empirically-observed near-maximum-entropy gamma distributions and the crystalline limit of Gaussian distributions governed by the central limit theorem. These results highlight a universal consequence of intrinsic biological noise on the architecture of certain tissues.Comment: 25 pages, 8 figures including S

    Effects of commercial fishing regulations on stranding rates of bottlenose dolphin (Tursiops truncatus).

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    Fisheries management actions taken to protect one species can have unintended, and sometimes positive, consequences on other species. For example, regulatory measures to reduce fishing effort in the winter gillnet fishery for spiny dogfish (Squalus acanthias) off North Carolina (NC) also led to decreases in the number of bycaught bottlenose dolphins (Tursiops truncatus). This study found that a marked decrease in fishing effort for spiny dogfish in NC also corresponded with a marked decrease in winter stranding rates of bottlenose dolphins with entanglement lesions (P= 0.002). Furthermore, from 1997 through 2002, there was a significant positive correlation (r2 = 0.79; P= 0.0003) between seasonal bycatch estimates of bottlenose dolphins in gill nets and rates of stranded dolphins with entanglement lesions. With this information, stranding thresholds were developed that would enable the detection of those increases in bycatch in near real-time. This approach is valuable because updated bycatch estimates from observer data usually have a time-lag of two or more years. Threshold values could be used to detect increases in stranding rates, triggering managers immediately to direct observer effort to areas of potentially high bycatch or to institute mitigation measures. Thus, observer coverage and stranding investigations can be used in concert for more effective fishery management
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