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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Effects of mono-ammonium phosphate and preceding crop on plant cadmium uptake

Amarakoon, Inoka 22 June 2010 (has links)
Cadmium (Cd) is a potentially toxic trace element. Two growth chamber studies were conducted to understand how: i) mono-ammonium phosphate affects durum wheat, flax or canola Cd uptake due to fertilizer induced changes in soil solution and plant; ii) preceding canola and barley affect the Cd uptake of subsequent durum wheat or flax. Durum wheat and flax shoot Cd concentrations were greater when grown on previous crop canola soil than when grown on previous crop barley soil regardless of what type of crop residue, if any, was added. The increase in Cd uptake for durum wheat and flax when on canola soil was probably due to increased availability of Cd in soil. Conversely, the application of mono-ammonium phosphate – reagent grade and the incorporation of preceding crop residue did not increase the crop Cd uptake of canola, durum wheat or flax and durum wheat or flax, respectively.
2

Effects of mono-ammonium phosphate and preceding crop on plant cadmium uptake

Amarakoon, Inoka 22 June 2010 (has links)
Cadmium (Cd) is a potentially toxic trace element. Two growth chamber studies were conducted to understand how: i) mono-ammonium phosphate affects durum wheat, flax or canola Cd uptake due to fertilizer induced changes in soil solution and plant; ii) preceding canola and barley affect the Cd uptake of subsequent durum wheat or flax. Durum wheat and flax shoot Cd concentrations were greater when grown on previous crop canola soil than when grown on previous crop barley soil regardless of what type of crop residue, if any, was added. The increase in Cd uptake for durum wheat and flax when on canola soil was probably due to increased availability of Cd in soil. Conversely, the application of mono-ammonium phosphate – reagent grade and the incorporation of preceding crop residue did not increase the crop Cd uptake of canola, durum wheat or flax and durum wheat or flax, respectively.
3

Priešsėlio poveikio vasarinių kviečių veislių produktyvumui ir sėklų kokybės rodikliams tyrimai / Researches of preplant impact on spring seed variety production and seeds quality indicators

Šiūpelytė, Vaida 16 June 2014 (has links)
Magistrantūros studijų baigiamajame darbe pateikiami 2013 metų vasarinių kviečių veislių, sėtų po skirtingų priešsėlių, derlingumo ir sėklų kokybės rodiklių duomenys ir atliktas priešsėlių poveikio veislėms įvertinimas. Darbo objektas - vasariniai kviečiai 'Triso' ir 'Hamlet', sėti po skirtingų priešsėlių (vasarinių miežių ir vasarinių rapsų). Darbo metodai ir vieta. Tyrimai vykdyti 2013 m. Vilmos Žliobienės ūkyje, Antušavos kaime, Kėdainių rajone. Eksperimento įrengimo vietoje dirvožemis karbonatingas glėjiškas rudžemis (RDg4-k2). Buvo nustatytas grūdų derlingumas, derliaus struktūros komponentai (produktyvių stiebų skaičius, vidutinis grūdų skaičius varpoje, 1000 grūdų masė, varpos produktyvumas). Grūdų kokybės rodikliai (baltymų, šlapiojo glitimo, krakmolo kiekis, sedimentacijos rodiklis ir kiti) nustatyti AB :Linas agro" laboratorijoje. Darbo rezultatai. Esmingai didžiausias derlingumas (5,9 t ha-1) ir 1000 grūdų masė (43,84 g) nustatyti `Hamlet` veislės vasariniams kviečiams po vasarinių rapsų priešsėlio. Patikimai didžiausias produktyvių stiebų skaičius (432,8 vnt. m-2) ir vidutinis grūdų skaičius varpoje (34,8 vnt.) buvo `Triso` veislės augalų. Genotipo (veislės) savybės ir 1000 grūdų masė turėjo didesnę įtaką grūdų derlingumui ir esmingai padidino ‘Hamlet` veislės derlingumą. Esmingai didžiausias vasarinių kviečių grūdų baltymų (14,9 proc.) ir sedimentacijos rodiklis (71 proc.) nustatytas ‘Triso‘ veislės grūduose po vasarinių rapsų priešsėlio. Esmingai didžiausias... [toliau žr. visą tekstą] / In Master's thesis is a submitted spring wheat variety of 2013, which were sown under different preceding crops, yield and seed quality indicators in data and performed assessment of preceding crop varieties impact. The object. Spring wheat 'Triso' and 'Hamlet', which were sown after different preceding crops (spring barley spring oilseed rape). Working methods and location. Research was carried out in 2013 at Vilmos Žliobienės farm in the Antušavos village in the Kėdainių area. The soil is endohypogleyic cambisol (RDg4-k2) at installation site of the experiment. It was established grain yield, harvest structure components (the number of productive stems, average number of wheat-ear, 1000 grain weight, productivity of wheat-ear). Grain quality indicators (protein, wet gluten, starch content sedimentation rate and others) were determined at AB Linas Agro laboratory. Results. Essentially the highest grain yield (5.9 t ha-1) and 1000 grain weight (43.84 g) were obtained in the fields of `Hamlet` variety, which were sown after spring oilseed rape. Reliably largest number of productive tillers number (432.8 units. m-2) and the average number of grains per ear (34.8 pc) was the variety of `Triso` compared to the variety of `Hamlet`, which was investigated in the same influence of forecrop. But a variety of properties and weight of 1,000 grain had a greater impact on grain yield and substantially increased varieties of 'Hamlet `yield. Substantially the largest spring wheat grain... [to full text]
4

Present with an Uncertain Future: Dispositional Mindfulness, Covariation Bias, and Event-Related Potential Responses to Emotional Stimuli in Uncertain Contexts

Goodman, Robert J. 01 January 2014 (has links)
Uncertainty represents a robust threat that can amplify aversive experiences and exaggerate negative expectations about uncertain future outcomes. Mindfulness – an open and receptive attention to present moment experiences -- has been shown to facilitate adaptive regulation when faced with a variety of distinct emotional threats. Reduced experiential avoidance and equanimity in the face of unpleasant emotional experiences have been theorized as central to these emotional regulatory benefits. The present study explored whether dispositional mindfulness would promote adaptive responses to uncertainty during the anticipation of, and after exposure to emotional stimuli, as indicated by self-reports and neural (event-related potential) markers of anticipation and appraisal. Participants were exposed to stimulus cues that informed them about the valence of a subsequent emotional picture as neutral, aversive, or uncertain. Consistent with past research, uncertainty during the anticipation of an emotional stimulus amplified unpleasant stimulus appraisals, and participants demonstrated biased expectations to associate uncertainty with aversiveness. Dispositional mindfulness was associated with lower expectations for unpleasant stimuli, and was found to amplify the effect of uncertainty on a cortical marker of stimulus appraisal called the late positive potential (LPP). Traits that contrasted with mindfulness predicted opposite patterns of association with these measures. However, these findings were directly the opposite of findings from past research. A theoretically defensible explanation is discussed for these findings and suggestions were made for future research on the role of mindfulness on ERP variability. The results from the present study contribute to a growing body of evidence that suggests that uncertainty during the anticipation of potentially negative future outcomes can exert a potent downstream influence on emotional anticipation and appraisal processes. Further research is needed to clarify the role of dispositional mindfulness during emotional stimulus anticipation and appraisal following uncertainty.
5

Offline Feedback Utilization for a Manual Aiming Movement Performed Under Conditions of Randomized Visual Feedback Availability

Cheng, Darian 13 January 2010 (has links)
Two studies were devised to determine why the difference in manual aiming performance, between full vision and no vision, is decreased for a randomized visual feedback schedule. In study one, aiming accuracy and precision was assessed for up to four trials in the same vision condition, following a switch in visual feedback availability. In experiment one, visual feedback availability was uncertain; while in experiment two, certainty was provided. Results of both experiments revealed that the precision of the first trial immediately following the switch in visual condition was reminiscent of the trial that preceded it, even when performed under different visual conditions. For study two, the inter-trial interval was evaluated by extending the interval to five seconds. Results indicated no reminiscence effect. Overall, we suggest that when the inter-trial trial is brief, individuals rely on offline visual information from the preceding trial to plan the subsequent movement, regardless of certainty.
6

Offline Feedback Utilization for a Manual Aiming Movement Performed Under Conditions of Randomized Visual Feedback Availability

Cheng, Darian 13 January 2010 (has links)
Two studies were devised to determine why the difference in manual aiming performance, between full vision and no vision, is decreased for a randomized visual feedback schedule. In study one, aiming accuracy and precision was assessed for up to four trials in the same vision condition, following a switch in visual feedback availability. In experiment one, visual feedback availability was uncertain; while in experiment two, certainty was provided. Results of both experiments revealed that the precision of the first trial immediately following the switch in visual condition was reminiscent of the trial that preceded it, even when performed under different visual conditions. For study two, the inter-trial interval was evaluated by extending the interval to five seconds. Results indicated no reminiscence effect. Overall, we suggest that when the inter-trial trial is brief, individuals rely on offline visual information from the preceding trial to plan the subsequent movement, regardless of certainty.
7

Trumpų sėjomainos rotacijų agrobiologinis įvertinimas / Agrobiological Assessment of Short Rotations

Seibutis, Vytautas 29 September 2005 (has links)
Lithuania’s agricultural reform resulted in significant changes in land use, i.e. in the emergence of small individual farms. As a result, the formerly most popular 7, 8, 9-course crop rotations, or even 5-6-course crop rotations became inapplicable on small farms, especially on those not involved in animal production and cultivation of grass forage. Multiple-course crop rotations would disperse the same crops over several places, and the fields would not be unacceptably small. This is especially problematic for market farms, where it is intended to have 1-2-3 main crops and adequately alternate them. In foreign countries short rotations are a common practice in similar cases. However, in Lithuania short rotations have hardly been investigated, except for the sporadic research cases, therefore it is rather complicated to judge the feasibility of market crops growing in short rotations. When the area of cereals is increased in a crop rotation, it is more difficult to choose preceding crops, and continuous growing of crops becomes inevitable. It is of special relevance here to maintain soil fertility, moreover, the adverse effects of crops concentration manifest themselves much more severely than in any other system, namely, heavy occurrence of weeds, diseases and pests, soil depletion and fatigue. On cultivated Central Lithuania’s soils shortening of rotations and proper choice of preceding crops make it feasible to produce profitable, high quality agricultural production... [to full text]
8

Účetní závěrka v akciové společnosti / The financial statements in the joint stock company

Bílková, Eva January 2012 (has links)
The aim of this thesis is to describe the process of financial statements in the joint stock company in terms of Czech legislation. The thesis is divided into two parts, a theoretical part discusses the operations preceding the closing of accounting books, the closing ledger accounts and financial statements with focus on respecting the true and fair view of the company and subsequent accounting duties related to financial statements. The practical part follows analysing the steps of the financial statements of particular joint stock company. The whole text is based on real data and demonstrates some situations characterised in the theoretical part.
9

Modelování vlivu sněhových zásob na letní minimální průtoky v horských povodích / Modelling the impact of seasonal snowpack on summer low flows in mountain catchments

Nedělčev, Ondřej January 2017 (has links)
This thesis analyses the impacts of winter snowpack and subsequent spring and summer liquid precipitation on low flows in the warm season. Meltwater is an important source of groundwater recharge. From groundwater storage streams are donated during summer months. Snow accumulation during cold season is reduced and snowmelt occurs earlier, which is a result of climate change and leads to lower groundwater recharge rates. That is the reason why change in snow cover dynamics affects summer low flows. Main goals of this thesis are to analyse how snow cover affects low flows I warm season and to compare it with impact of spring and summer precipitation. A conceptual runoff model HBV-light has been used to simulate the snow water equivalent (SWE) and streamflow from three mountain catchments. The integrated multi-variable model calibration procedure was used to calibrate the model. The model was used to simulate the snow and streamflow from 1981 to 2014. Besides the mentioned simulation, two hypothetical scenarios have been performed. These two scenarios accounted for reduced spring and summer liquid precipitation. In the first scenario, precipitation after maximum annual SWE was reduced to 75% of the real measured precipitation. In the second scenario, precipitation was reduced to 50% of the real...
10

Ecological role of mycotoxins produced by Fusarium graminearum : consequences of the presence of deoxynivalenol (DON) in crop residues on the soil microflora and soil fauna / Rôle écologique des mycotoxines produites par Fusarium graminearum : conséquence de la présence de déoxynivalénol (DON) dans les résidus de culture sur la microflore et la faune du sol

Abid, Muhammad 11 December 2012 (has links)
Fusarium graminearum est un champignon pathogène des plantes, responsable de la fusariose de l'épi (plus connue sous le nom de Fusarium Head Blight : FHB) sur céréales, notamment sur le blé et le maïs. En interaction avec la plante, le champignon produit des mycotoxines, parmi lesquellse le déoxynivalénol (DON), dont la finalité pour le champignon producteur est méconnue mais qui sont toxiques pour les humains et les animaux. Ainsi la qualité des grains contribue fortement aux pertes de rendement observées et les résidus contaminés restent au champ. Une première revue bibliographique (Leplat et al 2012) a mis en évidence l'importance des résidus de culture (habitat écologique) pour la survie saprophyte du champignon, pour sa reproduction sexuée et pour l'établissement de l'inoculum primaire susceptible d'infecter la prochaine culture. Une seconde revue bibliographique a souligné les lacunes en ce qui concerne le rôle que les mycotoxines pourraient jouer dans la survie de F. graminearum dans un cet habitat. L'objectif principal de cette thèse était donc de vérifier si la présence de mycotoxines dans les résidus de récolte donne un avantage compétitif à F. graminearum vis-à-vis des composantes biotiques du sol et des résidus et notamment les champignons, les bactéries, les protozoaires, les nématodes et les vers de terre. L'impact du DON sur ces différentes communautés a été évalué dans des résidus de maïs et de blé, au champ et en microcosmes, en condition de labour et de travail superficiel du sol. Le développement de la maladie et ses conséquences sur le rendement ont été observés dans l'expérience de terrain à l'Unité Expérimentale de l'INRA de Dijon.Au cours de cette étude, la survie et les dynamiques de développement de la souche modèle d'étude F. graminearum MIAE00376 et des communautés fongiques et bactériennes ont été mesurées en utilisant la réaction de polymérisation en chaîne en temps réel (Q-PCR) ainsi que par comptage sur boîtes. Dans le même temps, l'évolution des structures des communautés microbiennes a été déterminée par analyse du polymorphisme de longueur des fragments de restriction terminaux (T-RFLP). Les nématodes et les vers de terre ont été quantifiés par extraction et observations à l'œil ou a la loupe binoculaire. Le DON introduit dans le sol et les résidus a été extrait et quantifié au cours du temps par chromatographie liquide haute performance (CLHP). Des dynamiques de population de la souche MIAE00376 associée à différents microorganismes isolés de paille en décomposition et sélectionnés pour leur résistance au DON, à des bactéries fixatrice d'azote et à des Fusarium sp. appartenant au complexe fongique du FHB ont été mesurées en microcosmes de paille en présence ou non de DONLes résultats suggèrent que le DON dans les résidus de culture a une incidence sur les composantes biotiques du sol, mais l'impact dépend des communautés et de la localisation des résidus (en surface ou incorporés dans le sol). La biomasse moléculaire montre que les densités bactériennes et fongiques ont été significativement affectées par la présence de DON. La présence de DON a joué un rôle significatif sur la structure des communautés bactériennes et protozoaires, plus faible sur les communautés fongiques et nul sur les nématodes voire positif sur les vers de terre.Il est conclu que le DON est rapidement inaccessible en profondeur et un peu moins rapidement en surface (immobilisation ou dégradation), qu'il ne confère pas d'avantage compétitif au champignon producteur et que la gestion de l'habitat privilégié que constituent les résidus de culture pour F. graminearum peut être envisagée par le travail du sol en favorisant la décomposition rapide des résidus, par le labour ou l'utilisation d'organismes décomposeurs indigènes ou introduits. / Fusarium graminearum is a plant pathogenic fungus, causing devastating disease “Fusarium head blight” (FHB) in cereals including wheat and maize. It also contaminates the grains with mycotoxins including deoxynivalenol (DON) which are toxic to human and animals. This disease has resulted in the serious losses in grain yield and quality. We established through a first bibliographic review that during off season fungus survives saprophytically on the crop residues (ecological habitat) and serves as primary inoculum for the next season crop. However, we noticed also that the literature was poor about the role mycotoxins could play in the establishment of F. graminearum in such a habitat. The main aim of this thesis was therefore to test whether the presence of mycotoxins in the crop residues gives an advantage to F. graminearum to survive and develop a primary inoculum in the presence of the whole soil biota including fungi, bacteria, protozoa, nematodes and earthworms. We studied the impact of DON on the soil communities in the field as well as in microcosms, in wheat as well as in maize residues under tillage and no-tillage conditions. The disease development and the yield were noted in the field experiment. Some DON resistant active fungal decomposers and nitrogen fixing bacteria were picked and the dynamics of F. graminearum was observed by accelerating decomposition of crop residue in their presence, in the presence or absence of DON.During this study, the dynamic and survival of F. graminearum and total fungal and bacterial communities were examined by using quantitative real time polymerase chain reaction (qPCR) as well as by plate counting. At the same time, the structures of microbial communities were determined by using terminal restriction fragment length polymorphism analysis (T-RFLP). The DON resistance of isolated fungal decomposers and nitrogen fixers was tested by using minimal inhibitory concentration test (MIC). Nematodes and earthworms were quantified through binocular observations. The fate of DON was determined by quantifying the mycotoxin by high performance liquid chromatography (HPLC).The results suggested that DON in crop residues showed an impact on the biotic components of the soil but the impact depended on the communities and on the location of the residues (on surface or incorporated in the soil). The molecular biomass shows that the fungal and bacterial densities were significantly affected by the presence of DON. The presence of DON played significant role on the structure of bacterial and protozoan community while the nematodes and fungal communities remained unaffected. MIC results showed that the susceptibility of some competitive fungal strains towards DON was dependent on the dose of mycotoxin. The earthworms (Lumbricus terrestris) were not affected by the presence of mycotoxin. The degradation of DON in the residues was dependent on the time, the location of residues and the soil biota. The quantification of F. graminearum suggested that the presence of DON gave no advantage in the survival and development of primary inoculum during the decomposition of crop residues in the soil. We conclude that fungal decomposers can be selected on their enzymatic potential towards organic matter more than on the DON resistance to increase the degradation of the straw left at the surface and limit the subsequent development of F. graminearum.

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