967 research outputs found

    Evocative Narrative as Educational Research

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    After thirty years of teaching others how to teach, I enter a doctoral program to explore the question of how lived experience informs professional practice. Moving into the centre of my own doubts, I discover multiple selves, suffer death and rebirth, and ruminate on the nature of transformational learning

    Income Diversification of Farm Households: Relevance and Determinants in Germany

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    During recent years, the number of farms able to generate satisfactory income from agricultural production has continuously decreased in advanced economies. The main reasons are the implementation of the Common Agricultural Policy of 1992 and the increasing capitalization of the primary sector. The relevance of income diversification and interest in various development paths of rural households have, therefore, been renewed in political-economic debates in those countries. The aim of this study is to identify factors that determine income diversification in Germany. An econometric model has been estimated based on a comprehensive survey’s data. The results show that the main economic incentive for farm diversification is the expected income increase or resource allocation, whereas risk minimization is less relevant. Access to resources (labor, capital) is an important requirement for tapping alternative economic activities. Other significant variables include the education of the farmer as well as his experience in managing the farm. These findings are relevant for designing effective agricultural policy measures to explicitly meet the heterogeneous needs of the rural households.Income diversification, farm household, survey, Germany, Consumer/Household Economics,

    Numerical modeling of periodic pumping tests in wells penetrating a heterogeneous aquifer

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    This study investigated how to utilize multiple frequency components of pressure data from periodic pulse tests to estimate the intra-well permeability and compressibility distribution and also the presence of heterogeneities in a real field case. Periodic well testing is a technique in which injection or production pulses of a fluid are applied to a well in a periodic fashion. One of its main advantages is that ongoing operations do not have to be interrupted during the test as the superposed harmonic components can be identified using Fourier analysis. Further, modeling calculations are much faster than calculations in the time domain as no time-stepping is required and only the frequencies observed in the test need to be evaluated. We applied an earlier developed numerical code in the frequency domain to evaluate periodic-test results in a shallow aquifer and obtained a good match between data and calculations. The interpreted formation heterogeneity is in line with the local geology. Joints of various orientations constitute the main hydraulic conduits of the tested subsurface but they do not directly connect the wells. Thus communication between the wells has to be established through low-permeability features. The interwell periodic testing has corroborated the geological understanding of the aquifer and helped understanding the fluid flow pattern

    Two new species of Genoplesium R.Br. sensu lato (Orchidaceae: Prasophyllinae) from the Central Coast of New South Wales

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    We describe two new species of Prasophyllinae from New South Wales, in the genus Genoplesium R.Br. following the generic classification currently in use at the National Herbarium of New South Wales. One of these new species, Genoplesium branwhiteorum M.A.M.Renner & P.H.Weston, which we name for the Branwhite family, has been known for nearly a decade under the informal name Corunastylis sp. Charmhaven (NSW896673). The other new species, G. geminatum M.A.M.Renner & Towle has been confused with both G. rufum (R.Br.) D.L.Jones & M.A.Clem. and G. trifidum (Rupp) M.A.M.Renner, although it is more similar to G. mucronatum (Rupp) M.A.M.Renner and G. tasmanicum D.L.Jones, and possesses a combination of features of consistent expression supporting its recognition as a new species. Three new combinations are made. Genoplesium cuspidatum (D.L.Jones & L.M.Copel.) M.A.M.Renner, comb. nov. is based on Corunastylis cuspidata D.L.Jones & L.M.Copel., Genoplesium laminatum (Fitzg.) M.A.M.Renner, is based on Prasophyllum laminatum Fitzg. and Genoplesium mucronatum (Rupp) M.A.M.Renner is based on Prasophyllum mucronatum Rupp. [listed as a synonym of G. rufum in PlantNet]

    A review of Dendrobium kingianum Bidwill ex Lindl. (Orchidaceae) with morphological and molecular-phylogenetic analyses

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    Populations of Dendrobium kingianum Bidwill ex Lindl. from near Newcastle, New South Wales to southern and central west Queensland and encompassing all regions of the distribution were studied using field observations, morphometric analysis and nrITS sequences. A total of 281 individuals were used to construct regional descriptions of D. kingianum and 139 individuals were measured for 19 morphological characters, and similarities and differences among specimens summarised using multivariate statistical methods. Patterns of morphological variation within D. kingianum are consistent with a single variable species that expresses clinal variation, with short growing plants in the south and taller plants in the northern part of the distribution. The nrITS gene tree suggests two subgroups within D. kingianum subsp. kingianum, one comprising northern, the other southern individuals, which may overlap in the vicinity of Dorrigo, New South Wales. The disjunct D. kingianum subsp. carnarvonense in central west Queensland, which can be distinguished by a predominately subterranean habit and a narrower labellum midlobe, was resolved sister to D. moorei, which renders D. kingianum paraphyletic in the nrITS gene tree, but this position was not supported. Regional descriptions documenting clinal variation are provided. All previously described varieties, including D. kingianum var. pulcherrimum Rupp, are colour and growth forms of D. kingianum subsp. kingianum

    Decreased oxygen permeability of EVOH through molecular interactions

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    Poly(ethylene-co-vinyl alcohol) of 48 mol% ethylene content was modified with N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-isophthalamide (Nylostab SEED) to decrease the oxygen permeability of the polymer. The additive was added in a wide concentration range from 0 to 10 wt%. The structure and properties of the polymer were characterized with various methods including differential scanning calorimetry, X-ray diffraction, mechanical testing, optical measurements and oxygen permeation. Interactions were estimated by molecular modeling and infrared spectroscopy. The results showed that oxygen permeation decreased considerably when the additive was added at less than 2.0 wt% concentration. The decrease resulted from the interaction of the hydroxyl groups of the polymer and the amide groups of the additive. The dissolution of the additive in the polymer led to decreased crystallinity, but also to decreased mobility of amorphous molecules. Stiffness and strength, but also deformability increased as a result. Above 2 wt% the additive forms a separate phase leading to the deterioration of properties. The success of the approach represents a novel way to control oxygen permeation in EVOH and in other polymers with similar functional groups capable of strong interactions

    Konzept zur Reduktion der Regenfleckenkrankheit - Ermittlung von Parametern zur Biologie der Erreger unter westeuropäischen Klimabedingungen als Grundlage für die Weiterentwicklung eines Prognosemodells

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    Ziel des dreijährigen Projekts war es, Schlüsselparameter der bisher unter europäischen Bedingungen nur wenig erforschten Regenfleckenkrankheit (RFK) zu erarbeiten. In den Regionen Altes Land und Bodensee dominierte in allen drei Versuchsjahren (2007 – 2009) ein und derselbe RFK-Erreger, Peltaster sp.. Weitere RFK-Erreger sowie der Erreger der Fliegenschmutzkrankheit (FSK), Schizothyrium pomi, kamen nur sporadisch vor und sind wahrscheinlich für die Bekämpfung der Symptome derzeit ohne Bedeutung. In beiden Regionen ist die RFK fast ausschließlich auf ökologisch bewirtschaftete Anlagen beschränkt. Eine Besiedlung von Obstanlagen durch RFK-Erreger findet zunächst von außen statt, kann dann aber in den darauf folgenden Jahren durch endogenes Inokulum getragen werden. Fruchtmumien spielen eine Rolle als endogene Infektionsquellen. Umfangreiche Versuche zur Präzisierung der Infektionsbedingungen haben ergeben, dass eine Besiedlung der jungen Früchte bereits zum sehr frühen Zeitpunkt (T-Stadium, BBCH 74) und danach während des gesamten weiteren Saisonverlaufs erfolgen kann. Die Stärke der Symptomausprägung zur Ernte ist in erster Linie davon abhängig, wie lange die Früchte den natürlichen Infektionsbedingungen ausgesetzt waren. Je später in der Saison Infektionen stattfinden, desto weniger Zeit haben die RFK-Pilze für die Besiedlung und Ausbreitung auf der Frucht, so dass späte Infektionen i.d.R. nicht mehr zu starken Befallsgraden führen. Zur Ausprägung von RFK-Symptomen ist Blattfeuchte, auch in Form von Taubildung, ausreichend, jedoch wird die Symptomausbildung mit zunehmenden Niederschlagsmengen deutlich beschleunigt. Sind erste RFK-Symptome in einer Anlage sichtbar, verkürzt sich die zur Inkubation notwendige kumulative Blattnässedauer von etwa 250 auf unter 150 Stunden. Die RFK-Erreger scheinen eine mehrwöchige Trockenphase unbeschadet überdauern zu können. Apfelsorten zeigen deutliche Unterschiede in der Ausprägung der RFK-Symptome. Die Ursachen hierfür müssen in weiteren Untersuchungen geklärt werden
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