Strategies for administration of biosurfactants-producing pseudomonads in closed hydroponic systems

Zoospore-producing oomycetes are major plant pathogens of particular concern in hydroponic systems. Compared with pesticides, biocontrol using antagonistic microorganisms is a sustainable approach to control oomycetes. Previous research has demonstrated that biosurfactants and biosurfactant-producing microorganisms are potentially useful components of a sustainable biocontrol strategy. In this study three ways of supplying a biosurfactant-producing strain to a recirculating hydroponic cultivation system infected with a zoospore-producing plant pathogen were evaluated. The strain P. koreensis 2.74 was added as washed cells, in its spent KB broth or in a minimal medium adapted from the nutrient solution, and compared with control treatments. A significant reduction in disease with up to 50% was achieved when a high concentration of washed cells was added weekly to the plant cultivation system. The disease suppression obtained through addition of washed cells equalled the effect achieved when the purified biosurfactant was used. Phytotoxicity was observed when the spent broth was included in the treatment

A cryptic sulfur cycle driven by iron below the sulfate-methane transition zone

My Ph.D thesis deals with biogeochemical cycling of carbon, sulfur and iron compounds in marine sediments on the continental shelves in relation to the activity and distribution of sulfate-reducing bacteria below the sulfate-methane transition. The aim of the first report was to study sulfate reduction and sulfur-iron geochemistry in deep gravity cores of Holocene mud collected from Bay of Aarhus (Denmark). It was the goal to understand if sulfate is generated by reoxidation of sulfide throughout the sulfate and methane zones and try to explain the abundance of active sulfate-reducers deep below the main sulfate zone from geochemical processes (i.e. oxidation of sulfide with iron oxides). We did potential sulfate reduction rate experiments, where extra sulfate and organic substrates were added to sediment sub-samples that were incubated in time series experiments. Sulfate reduction rates in the sulfate-rich sediment layers were high due to the high concentration of reactive organic matter. In the methane zone, sulfate remained at background concentrations of <0.5 mM down to the sulfidization front and sulfate reduction decreased steeply to rates, which at 300-500 cm were 0.2-1 pmol SO42- cm-3 d-1, i.e. four to five orders of magnitude lower than rates near the sediment surface. The potential sulfate reduction rates were found to be 10-40-fold higher than the sulfate reduction rates estimated without extra electron donor-and acceptors added to the sediment. This demonstrated that a physiologically intact community of sulfate-reducing bacteria was present deep below the sulfate-methane transition zone. The background sulfate concentration appears to be generated from the reaction of downwards diffusing sulfide with deeply buried Fe(III) species, such as poorly-reactive iron oxides or iron bound in sheet silicates. The oxidation of sulfide to sulfate in the sulfidic sediment may involve the formation of elemental sulfur or perhaps thiosulfate and the further disproportionation of a small fraction to sulfate. The net production of sulfate from the reaction of sulfide and Fe(III) to form pyrite requires an additional oxidant. This could be CO2 which is reduced to methane and subsequently becomes re-oxidized at the sulfate-methane transition and thereby removes excess reducing power. The second report describes the sediment and pore water geochemistry of long sediment cores collected in the Arkona Basin of the south-western Baltic Sea. We observed an unusual sulfate profile deep within the limnic deposits, by which high concentrations of sulfate were present in the pore water. The study indicated that the high sulfate concentrations within the sub-surface sediment layers of the Arkona Basin were not due to oxidation of reduced sulfur species as previously assumed, but rather due to downward diffusion of sulfate during the early Holocene history of the Baltic Sea. The third report presents data from sediment collected in the western part of the Black Sea. The study demonstrated that sulfate-reducing bacteria were active also several meters below the sulfate-methane transition in Black Sea sediments. The cryptic sulfate reduction below the sulfate-methane transition may be driven by sulfate produced from reoxidation of sulfur compounds in pore water and sediment with oxidized iron minerals. The fourth report aimed to investigate the association between phosphate release, organic phosphorus mineralization, and dense communities of the filamentous sulfur bacteria, Thioploca spp., on the continental shelf off central Chile. We found that the pore water was super-saturated with respect to hydroxyapatite but the concentration of authigenic apatite in the sediment was only a minor P-component in the sediment and most solid-phase phosphate was bound to iron. The large phosphate release was not directly related to the presence of Thioploca but rather the result of a high deposition and mineralization rate of fresh organic detritus

Effekten av djupbearbetning på potatisskörd och jordstruktur

Agriculture practices today include the use of heavy machinery which leads to soil compaction. High soil strengths are known to restrict the root development and prevent root growth. Sandy soils, which often are used in potato production, seem to be especially susceptible to subsoil compaction. Subsoiling is a way to loosen up the plough pan by deeper tillage. General it decreases soil strength and bulk density, the effect is that the roots can penetrate further down in the soil which may reduce stress caused by inadequate water and nutrient supply. The persistence of subsoiling is dependent on several factors such as soil moisture at the time of subsoiling, the choice of subsoiling equipment and traffic practices following the subsoiling. The best way to prevent recompaction is to apply controlled wheel traffic. The conclusion from my literature study is that under near optimum irrigation levels subsoiling are of no benefit to the yield but during more drought conditions the additional rooting volume significantly increase potato yields, but have no effect on the quality. Therefore subsoiling can be of importance in areas were irrigation is not used.Idag används mycket tunga maskiner i lantbruket, vilket orsakar skador på jordens struktur och därmed ger sammanpackade jordar. Packskadorna uppstår ofta precis under normalt plöjningsdjup och bildar då en så kallad plogsula. Rötterna har svårt att tränga igenom plogsula och resultatet kan bli ett grundare rotsystem som gör att växten stressas av vatten- och näringsbrist. Djupbearbetning kan lösa upp plogsulan och underlätta rotpenetreringen, därigenom kan stress undvikas. Hur länge effekten av djupbearbetning kvarstår beror på flera faktorer, så som markfukt vid bearbetningen, val av utrustning samt körrutiner efter djupbearbetningen. Bästa sättet att reducera packskador är att använda sig av permanenta körspår. Slutsatsen från min litteraturstudie är att djupbearbetning inte har någon inverkan på skörden vid optimal vattenförsörjning men under torra förhållanden ger den ökade rotvolymen en signifikant ökning av skörden. Därför kan djupbearbetning vara att rekommendera i odlingar där bevattning inte används

Investigation of Post-Processing Resistivity Modification Methods for HV-CMOS Pixel Detectors

Silicon detectors plays a key-role in the measurement of particle trajectories in cur- rent particle collision experiments. Future colliding experiments will impose even larger demands on the performance of the detectors. To meet these demands, while simulta- neously keeping costs low, monolithic active silicon sensors using HV-CMOS technology are currently investigated. While showing good promise, many semiconductor foundries do not allow for custom substrate resistivity, making it interesting to investigate whether standard substrate HV-CMOS sensors are a viable option for future high energy particle detectors. To this end, this thesis presents a study on how the charge collection and effective doping concentration are affected by hadron irradiation in HV-CMOS detector prototypes. The investigated prototypes were produced at two different foundries, Austria Micro Systems and LFoundry, and were irradiated with either protons or reactor neutrons. Edge-TCT, using pulsed IR light injection, was the main tool of investigation. Proton irradiated samples were found to perform significantly better after fluences of 5 · 1014 neq/cm2. The neutron irradiated samples had a significant reduction charge collection in spite of an increased depletion region after 1015 neq/cm2. Additionally, all samples showed a decrease in charge collection in the fluence region 1013 - 1014 neq/cm2. Following these, low-resistivity HV-CMOS detectors might not be optimal for some particle collider environments, but could be of use for prototyping with foundries not offering custom resistivity substrates. Additionally, as an attempt to improve performance Thermal Donor introduction was investigated as a method to increase the active region in low resistivity HV-CMOS sensors. Samples were annealed at 450 ◦C at increasing time intervals, and measured using edge-TCT. Introduction rates were found to deviate greatly from estimated values, and Thermal Donor introduction was ultimately concluded not viable as a method to improve detector performance

Effect of liming and free Ca2+ on Cd uptake of carrots, Daucus carota

The level of cadmium (Cd) in Swedish arable land has increased during the last century and the average concentration of Cd in the plough layer is today 0.23 mg/kg. The increase is mainly due to anthropogenic activities such as phosphorus fertilizing, liming, import of feed, and atmospheric deposition from industrial emissions. Cadmium in the soil will be taken up by crops and is thereby transferred to humans via food. Carrot is one of the crops of concern, both because it may contain quite high Cd concentrations and due to the large consumption in Sweden. In the body, Cd is stored mainly in the liver and the kidneys and may cause several diseases already at low concentrations. Due to these findings, the recommendation for Cd intake has recently been lowered and should not exceed 2.5 µg per kg body weight/ week. This means 25 µg per day for a person weighing 70 kg. To decrease the Cd uptake by plants liming is often recommended, however the results of liming are inconsistent. When adding lime several soil factors, such as pH, Ca concentration, and ion strength is altered which may affect the Cd availability and uptake by plants. The aim of this Master thesis was to study the effects of liming and Ca2+ on the Cd uptake by carrots. In order to do that, two experiments were conducted. The long-term experiment was conducted in a climate chamber where the carrots were grown in a sand/peat substrate for eleven weeks. Two levels of Cd were tested, 0.23 and 2.3 mg/kg soil, in combination with three pHs: 4.6, 5.6, and 6.6. The pH was altered by addition of lime. In the short-term experiments the Cd uptake by plants was tested in nutrient solutions. Two different pH levels were used, 5.6 and 6.6. Each pH was combined with three levels of Ca, 2.25, 4.5, and 9 mM. The results from the long term experiment showed increased Cd uptake with increasing pH. However, since the concentrations of Cd and Ca follow each other in all treatments and were well correlated to the plant weights it seems like the Cd uptake was mostly affected by plant growth. Results from the short-term experiment showed decreased Cd uptake with increasing pH. The results also indicate that high Ca concentrations may lower the Cd uptake. However the effect of Ca seems only to be valid at low pH

En öppen dörr - Enhetschefer om ledarskap och tillgänglighet inom äldreomsorgen

Abstract The media sometimes give a dark image of Swedish elderly care. Responsibility for the care of the elderly is put on the managers. Apart from budget matters, they are responsible for staff as well as care-takers. The aim of this study was to examine the manager role at homes for the elderly from the point of view of the managers themselves. The material consists of six semi – structured interviews with managers. The theory I used to do my analysis was the Human Resource – perspective and I chose to interview six managers that all worked at homes for elderly in Sweden. I found that the managers, in general, had high demands on their staff and that it was important for them to be present and available for both their staff and the elderly. Their discretion was more or less limited because of the fact that they were managers in mid-level but the thing that was most important for them was the wellbeing of both the elderly and their staff. Their opinions varied when it came to how much the elderly could decide over their time and ways of living. Some of my interviewed expressed that the elderly had very little to say about their everyday life while others was of the opinion that they were allowed to decide about almost everything. The main factors that affected this were the state of health of the elderly, their age, their relatives and the staff

Syntese og ionisk selvsamling af tyndfilm med lamellar struktur af Po4R og

N/A

Skillnad i inre och yttre motivation mellan offentligt och privat anställda

Studiens syfte var att undersöka om det finns skillnader i inre och yttre motivation hos anställda inom den offentliga och privata sektorn samt om inre och yttre motivation varierar beroende på upplevd livstillfredställelse, kön, ålder och inkomst. Data från en enkätundersökning med 88 offentligt och 98 privat anställda bekräftar svagt majoriteten av tidigare forskning som menar att privat anställda i högre grad drivs av motivationstypen yttre kontroll. Inget signifikant resultat uppmättes för att offentligt anställda skulle drivas mer av inre motivation. Enkäten bestod av demografiska frågor, samt två instrument; Work Extrinsic and Intrinsic Motivation Scale, för att mäta inre och yttre motivation, och Life Satisfaction Scale för att mäta upplevd livstillfredställelse. Studien visade även en skillnad mellan inre motivation och kön, mellan amotivation och ålder samt ett samband mellan inre motivation, amotivation och inkomst. Även skillnader mellan olika motivationstyper och upplevd livstillfredställelse hittades

Medarbetarskapet i fokus: En studie om skillnader i små och medelstora organisationer

Syftet med denna studie var att undersöka medarbetarskapet på ett antal butiker inom samma koncern med olika storlek för att se om det förelåg skillnader beroende på organisationernas storlek. Vidare undersöktes också om det förelåg någon skillnad mellan organisationerna i det upplevda medarbetarskapet beroende av arbetsledning med personalansvar, arbetsledning utan personalansvar eller ingen arbetsledning. Med detta ville vi tillföra ny kunskap på medarbetarskapets förhållande till organisationsstorlek då det tidigare finns begränsad forskning inom detta. Studien genomfördes på åtta små och tre medelstora butiker i Malmö stad och Lunds kommun. Materialet om medarbetarskapet samlades in genom frågeformuläret Work-Oriented Relationships and Knowledge-based Investigation Questionnarie (WORK-IQ) (Bertlett & Arvidsson, 2009), vilket innehåller följande åtta dimensioner: Kunskap och färdighet, psykologisk mognad, lärande, inomgruppskommunikation, mellangruppskommunikation, sociala relationer, demokratiska processer och slutligen tillit- lojalitet och respekt. Totalt samlades 115 komplett ifyllda formulär in. Resultaten visar att det finns signifikanta skillnader mellan små och medelstora organisationer i dimensionerna lärande och demokratiska processer men i övrigt verkar inte organisationsstorlek ha någon större inverkan på medarbetarskapet. Enligt resultatet verkar inte organisationens storlek heller påverka det upplevda medarbetarskapet beroende på om man har arbetsledning eller inte. Däremot verkar arbetsledning påverka medarbetarskap

IL-18Rα-deficient CD4+T cells induce intestinal inflammation in the CD45RBhitransfer model of colitis despite impaired innate responsiveness

IL-18 has been implicated in inflammatory bowel disease (IBD), however its role in the regulation of intestinal CD4+ T-cell function remains unclear. Here we show that murine intestinal CD4+ T cells express high levels of IL-18Rα and provide evidence that IL-18Rα expression is induced on these cells subsequent to their entry into the intestinal mucosa. Using the CD45RBhi T-cell transfer colitis model, we show that IL-18Rα is expressed on IFN-γ+, IL-17+, and IL-17+IFN-γ+ effector CD4+ T cells in the inflamed colonic lamina propria (cLP) and mesenteric lymph node (MLN) and is required for the optimal generation and/or maintenance of IFN-γ-producing cells in the cLP. In the steady state and during colitis, TCR-independent cytokine-induced IFN-γ and IL-17 production by intestinal CD4+ T cells was largely IL-18Rα−dependent. Despite these findings however, IL-18Rα−deficient CD4+ T cells induced comparable intestinal pathology to WT CD4+ T cells. These findings suggest that IL-18-dependent cytokine induced activation of CD4+ T cells is not critical for the development of T-cell-mediated colitis