Tesis para optar al Grado de Magíster en Ciencias Agropecuarias, Mención Sanidad Vegetal / Las Rizobacterias Promotoras de Crecimiento Vegetal (PGPR), son bacterias benéficas que viven en asociación con las raíces de las plantas, su uso en la agricultura puede disminuir la dependencia a agroquímicos tóxicos para el medio ambiente y la salud humana.Filtrados de siete cepas rizobacterianas, con características nematicidas, fueron evaluadas en condiciones in vitro, sobre los nemátodosfitoparásitosXiphinema index y Meloidogyne ethiopica. Seefectuaronuna serie de pruebas bioquímicas para determinar la presencia de algunos metabolitos y enzimas, con posible actividad nematicida.Finalmente, se identificaron las cepas mediante métodos moleculares y pruebas bioquímicas. Los resultados mostraron que después de 72 horas de exposición de los individuos de Xiphinema index a los filtrados rizobacterianos, hubo mortalidades del 94 y 100% con Bacillus amyloliquefaciens consorcio FR203A y Pseudomonas fluorescensFP805PU, respectivamente.Estas bacterias,en el mismo orden, tuvieron mortalidades del 76 y 83% en individuos de Meloidogyne ethiopica. Las otras cepas, tuvieron mortalidades desde 54 a 81% en Xiphinema index y 44 a 59% en Meloidogyne ethiopica. Cinco cepas tuvieron diferencias significativas con el tratamiento control en la eclosión de huevos deM. ethiopica, teniendo los mayores porcentajes de mortalidad las cepas Brevibacterium frigoritoleransFB37BR, B.amyloliquefaciensconsorcio FR203A y B. thuringiensisFS213P. Todas las cepas rizobacterianas tuvieron actividad en almenos cinco de los metabolitos y exoenzimas considerados. Las cepas rizobacterianas evaluadas, poseen compuestos con efecto nematicida, que pueden ser una alternativa interesante de control. / The plant grown-promoting rhizobacteria are beneficial bacteria that live in association with plant roots, their use in the agriculture can reduce the dependence on toxic chemicalsthat affect the environment and human health. Filtrates of seven rhizobacterial strains, with previously proved nematicidalproperties, were in vitroevaluated onMeloidogyne ethiopica and Xiphinema indexplant-parasitic nematodes. Sets of chemical tests were performed to determine the presence of certain metabolites and enzymes with possible nematicidal activity. The results after 72 hours exposure to rhizobacterial filtratesshowed a mortality of 94%and 100% onXiphinema index assayed with Bacillus amyloliquefaciens consortium FR203A and Pseudomonas fluorescensFP805PU, respectively. The same bacterial strains presented mortalities of 76 and 83%on Meloidogyne ethiopica, repectively. Concerning the otherbacteria strains, the mortality varied from 54-81% onXiphinema index and 44-59% onMeloidogyne ethiopica.Concerning the Meloidogyne ethiopica egg hatching assay, significant differenceagainst control treatmentoccurs only with five bacteria strains and the highest hatching control percentages presentedBrevibacterium frigoritoleransFB37BR, B. amyloliquefaciens consortium FR203A and B. thuringiensisFS213P. All rhizobacterial strains presented activity for at least five of themetabolitesand the exoenzymes considered. The rhizobacterial strains tested possess nematicidal compounds, which may be and interesting alternative of control.

Uit die tematologiese indeks blyk dat Oberholzer besonder waarde heg aan: Die ontologiese-antropologiese denkweg; die fenomenologiese werkwyse; die verhouding tussen onties en ontologies; opvoeding as lewensopvatlike gemoeidheid; wetenskap as bewussynsaangeleentheid; pedagogiek se relatiewe outonomie; die leefwêreldlike begronding van die Pedagogiek; behoorlikheidseise, waardes en norme; die menswording van die kind; die sin van pedagogiese kategorieë en kriteria; die pedagogiese essensies: gesag, geborgenheid, ontmoeting, openheid, steungewing, noodbelewing en volwassenheid as opvoedingsdoel.</p Die besondere persoonsindeks toon aan dat Oberholzer afkeurend staan teenoor skrywers wat naturaliste is, -isme denke as wetenskap beskou, pedagogiek as 'n toegepaste wetenskap sien, wat verabsoluteer of 'n karikatuur probeer maak van die fenomenologiese benadering, nie die grense van opvoeding raaksien nie, beweer dat opvoeding nie slegs moontlik is in die verhoudinge van volwassenes tot nie-volwassenes nie, wat nie die sin van die opvoeding ook as 'n besondere lewensopvatlike aangeleentheid raaksien nie, in 'n Cartesiaanse dualisme verval en blind is vir die feit dat outentieke pedagogiekdenke kategoriale denke is. Oberholzer staan goedkeurend teenoor skrywers wat die menslikheid van die mens nie misken nie; fenomenologie as ontologie bedryf; wetenskap ter wille van wetenskap beoefen; die aksiologies-etiese beklemtoon; die lewensopvatting sien as belemmerend by die opvoedkunde; maar noodwendig by die opvoeding; soek na pedagogiese begronding in die ontologies-antropologiese; die kindheid van die kind raaksien, wetenskaplike denke as kategorieë-aanwending sien; opvoeding sien as dialogiese aangeleentheid; pedagogiek sien as outonome wetenskap met toepassingsmoontlikheid; die ontologies-antropologiese denkweg volg; die idee van die paedagogica perennis nie bedreig nie. Uit die ondersoek na die besondere hoofaksente in die Oberholzerse pedagogiekdenke, blyk die beïnvloeding deur Heidegger, maar ook Oberholzer se insig in die betekenis van die kategoriee onties en ontologies vir 'n outentieke pedagogiekdenke. Vir Oberholzer behels wetenskapsbeoefening die denkende soeke na die ontiese; die openbaring van die oersynsgegewene wat ontologies verantwoordbaar is. Pedagogiekdenke is 'n besondere vorm van struktuurdenke en strukture het ontiese status. Pedagogiekdenke vereis kategoriee wat deursigtelikmakende middele en ontologiese gefundeerde ontwerpe vir die denke is. Oberholzer beklemtoon deurgaans dat die mens nie vasgevang kan word in 'n oorsaak-gevolg skema nie, maar dat dit essensieël gaan om die grande van menswees. Hy gebruik die Langeveldse "self-iemand-wees" uitspraak om die ontologiese gefundeerdheid van die pedagogiese aan te dui. Omdat hierdie uitspraak 'n suiwer ontologiese uitspraak is waarop alle menswetenskappe wat waarde heg aan 'n ontologiese gefundeerdheid, gegrond is, verontologiseer Oberholzer nie die pedagogiese nie, maar vestig die aandag op die ontologiese gefundeerdheid daarvan. Oberholzer soek vanuit pedagogiekperspektief in die ontologies-antropologiese synsfeer na die pedagogics relevante. Oberholzer as besondere kampvegter vir 'n outonome pedagogiek op grand van ontologiese begryping wat slegs langs fenomenologiese weg moontlik is, wil nie verontologiseer nie. Die pedagogiese gebeure is suiwer antropologiese gebeure, dus is 'n verantropologisering van die pedagogiese gebeure nie moontlik nie. Wie sê dat die mens wese is wat opvoed, dui 'n synsmodus van menswees aan en is verontologisering van die pedagogiese ook nie moontlik nie. Oberholzer toon ook die verband aan tussen lewensopvatting en opvoeding. Hy stel dit duidelik dat deskriptiewe waarderinge as wetenskapsbeoefening en preskriptiewe waarderinge as lewensopvatlike aangeleentheid ter wille van die wetenskapsbeoefening geskei moet word. Opvoeding, volgens Oberholzer, as universele verskynsel se praktykwording, is 'n lewensopvatlik bepaalde aangeleentheid. Die universele word partikulier wanneer daar bepaalde waardes, soos vergestalt in die lewensopvatting, gekies word. Keuse van bepaalde waardes impliseer standpuntstelling en dan is daar van neutraliteit geen sprake nie. Oberholzer bevestig telkens die onmoontlikheid van 'n neutrale opvoeding, want lewensopvatting bepaal die opvoedingspraktyk en pedagogiese oogmerke is ideologiese aangeleenthede. Dit is duidelik dat Oberholzer 'n neutrale pedagogiek en 'n nie-neutrale opvoeding voorstaan. ENGLISH : From the thematic index it becomes evident that Oberholzer attaches much value to: the ontological-anthropological course of reflection; the phenomenological method; the relationship between ontic and ontological, upbringing as a matter of being involved in a view of life; science as a matter of conscious being; the relative autonomy of Pedagogics; grounding pedagogics in the life world; demands concerning propriety, values, norms; the child's becoming a human being; the meaning of pedagogic categories and criteria; the pedagogic essentials: authority, security, encounter, openness, support, experiencing need and adulthood as the goal of upbringing. An index of the authors referred to by Oberholzer shows that he disapproves of those authors who are naturalists; who regard absolutism in their reflection as science; in whose eyes pedagogics is an applied science, who are guilty of absolutism or of making a caricature of the phenomenological approach, who do not observe the limits of upbringing, who proclaim that the relationship between adults and children is not a prerequisite for upbringing, who do not regard the meaning of upbringing as a matter of a particular way of life, who are victims of a Cartesian dualism and who reject the fact that authentic pedagogic reflection implies categorical reflection. On the other hand Oberholzer approves of those authors who acknowledge the humaness of a human-being; who exercise phenomenology as ontology, who practise science for the sake of science, who emphasize the axiological-ethical, who regard view of life as a hindrance as far as pedagogics is concerned but essential for upbringing, who try to ground the pedagogical in the ontological-anthropological, who observes the essentials of the child's being a child, who regard scientific reflection as the application of categories; who regard upbringing as a matter of dialogue, who regard Pedagogics as an autonomous science having the possibility of being applied, who follow the ontological-anthropological course of reflection, whose viewpoints are not a threat to the idea of the paedagogica perennis. In an attempt to discover particular main accents in Oberholzer's pedagogic reflection the influence of Heidegger becomes evident but also Oberholzer's own insight regarding the significance of the categories ontic and ontological for authentic pedagogic reflection. Oberholzer regards the practising of a science as a reflective search for the on tic; as the revealing of that which is primordially given and ontologically accountable. Pedagogical reflection is a particular form of structure reflection and structureshave ontic status. Pedagogical reflection demands categories which are employed to make something lucid and are ontologically founded designs for reflection. Oberholzer emphasizes that a human being cannot be captured in a scheme of cause and effect, but it essentially concerns the foundation of being a human. He uses Langeveld's idea of being-a-person to prove that the pedagogical event is ontological founded. Because this is a purely ontological pronouncement on which all human sciences which attach value to an ontological foundation are based, Oberholzer does not deliver the pedagogical reflection to the ontological reflection but, instead, point out that it is ontologically founded. Oberholzer searches from a pedagogical point of view for that which is pedagogically relevant in the ontological-anthropological sphere. Oberholzer as an advocate of autonomous Pedagogics based on ontological understanding, which is only possible by implementing the phenomenological method, does not intend to ontologise. The pedagogic event is a purely anthropological event with the result that anthropologising the pedagogical event is not possible. Anybody who proclaims that a human being is somebody who brings up expresses a mode of being a human with the result that ontologising the pedagogical event is not possible. Oberholzer also shows the relationship between view of life and upbringing. He advocates a distinction between a descriptive appreciation as practising science and prescriptive appreciation as a matter concerning one's view of life. According to Oberholzer practical upbringing as an universal phenomenon is a matter inseperable from one's view of life. The universal becomes particular when a choice of certain values as manifested in a view of life is made. The choice of certain values implies that one adheres to a particular point of view - so that there is no question of being natural. Oberholzer confirms the impossibility of neutral upbringing because the view of life determines the practice of upbringing and pedagogical aims are ideological matters. It is clear that Oberholzer advocates neutral Pedagogics but a not-neutral upbringing. / Dissertation (MEd)--University of Pretoria, 1975. / Educational Psychology / unrestricted

No description available.

Rivercane, Arundinaria gigantea, is the native woody evergreen grass that has exhibited rapid population decline since European colonization of North America. Agriculture and urban expansion have reduced this important ecosystem type to remnant populations. This poses challenges to current restoration efforts by minimizing genetic diversity and limiting healthy host sites for propagation. Objectives of this research were to test four methods of establishment that would promote the greatest survivability and growth of propagules. Non-irrigated field studies indicated greatest rivercane growth response when planted in increased shade (60 - 85% light reduction). Monthly plantings indicated that February offered the greatest probability of survival. Application of slow release 19-6-12 fertilizer (33.3 g) enhanced growth, but fertilizer applications are not recommended without adequate soil moisture. Halosulfuron (72.6 g a.i./ha) applications for weed control showed no damage to rivercane plants compared to control.

The study of the structure-activity relationship of electrode surfaces is fundamentally important in electrocatalysis research. Yet, the methods and techniques used for the examination of structure-activity relationship so far are limited by their capabilities, and the exploration of electrochemistry at complex surfaces is very challenging. In this study, the correlation between the electrode surface structure and its corresponding activity in two electrochemical reactions were investigated: an electrochemical etching reaction and an electrocatalysis reaction. A polycrystalline Pt electrode was galvanically etched to expose the underlying well-defined crystallites serving as pseudo-single-crystal electrodes. Atomic force microscopy (AFM) complemented with electron backscatter diffraction (EBSD) was employed for the elucidation of the effects of electrode surface structure on its etching rate. Electrochemical measurements of the electrocatalytic activity of the hydrogen oxidation reaction on individual grain surfaces were performed with high spatial resolution scanning electrochemical microscopy (SECM) coupled with electron backscatter diffraction (EBSD). The etching experiment and surface characterization results show the more deeply etched regions on polycrystalline Pt surface correspond to Pt(100). The etching rate of the Pt catalyst is Pt(111), Pt(100), and Pt(110) in increasing order. The structure-reactivity relationship showed that the catalytic activity for hydrogen oxidation reaction (HOR) increases in the order Pt(100) < Pt(110) < Pt(111), where the Miller index plane represents the terrace orientation of the high-index facets. A clear correlation is observed between the increase in HOR activity and step sites density on a given base orientation. Quantitative kinetic measurements at crystal domains were made from current-potential plots and SECM approach curves.

No description available.

No description available.

No description available.

No description available.

Breeding objectives were developed for Targhee sheep at different levels of prolificacy and triplet survival. Economic weights (EW) were derived for estimated breeding values (BV) from National Sheep Improvement Program genetic evaluations for 120 d weaning weight (WW), maternal milk (MM), yearling weight (YW), fleece weight (FW), fiber diameter (FD), staple length (SL), and prolificacy (PLC; lambs born/100 ewes lambing). A commercial flock was simulated, accounting for nonlinear relationships between performance and profit. Ewes were assumed mated to sires of specified BV and profit was derived from lifetime performance of lambs and replacement females from that lamb crop. Economic weights were determined as change in profit from use of sires with BV that were one additive standard deviation above the mean for each trait [1.98 kg for WW, 1.62 kg for MM, 2.90 kg for YW, 0..36 kg for FW, 0.99 microns for FD, 0.74 cm for SL, and 17.58 lambs/100 ewes for LC], while holding all other BV at breed average. Separate breeding objectives were derived for different ways of meeting increased nutrient needs (P = purchase hay, R = rent pasture, and L= limited flock size) and for different market lamb values (D = discounting lamb value for heavy weights, ND = no discount for heavy lambs). Based on replicated simulations, relative EW did not vary with prolificacy or triplet survival (P > 0.15) but were affected by feed costs and lamb market values (P < 0.01). Selection indexes were derived within and across simulated scenarios, and correlation (r) among indexes of > 0.90 indicated that an index could be used across multiple scenarios with little loss of selection efficiency. Indexes derived within feed cost scenarios (P, R, and L) and lamb value scenarios (D, ND) were strongly intercorrelated (r > 0.97). Correlations among average indexes for feed cost scenarios (0.97 for R and P, 0.70 for R and L; 0.85 for P and L) indicated that two feed cost scenarios could be used depending on whether winter forage was limited (L) or not (NL). The correlation between average indexes for these two scenarios was 0.78. Indexes were presented for combinations of feed cost and lamb value scenarios. Two indexes were suggested, representing the scenarios that apply to a large portion of Targhee producers. These indexes were for discounting heavy lambs with limited winter forage (D-L: 1.0 WW + 0.14 MM __ 0.76 YW + 1.22 FW __ 0.36 FD - 0.09 SL + 0.25 LC) and discounting heavy lambs with additional available forage (D-NL: 1.0 WW + 0.24 MM __ 0.34 YW + 1.65 FW __ 0.41 FD - 0.14 SL + 0.33 LC). For a standardized selection differential of one for the index, the expected changes in mean index value were $2.17 and $1.92 per ewe per generation for D-L and D-NL, respectively. / Master of Science