3,070 research outputs found

    Sjukdomsidentifiering i potatis och strÄsÀd med luftburna multispektrala sensorer

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    Potato (Solanum tuberosum L.) and winter wheat (Triticum aestivum L.) fields with ongoing field trials testing use of fungicides were evaluated using two camer-as (RGB-sensors that registers light in the red (R), green (G) and blue (B) wave-length bands) and one multispectral sensor (that registers light in five narrow bands in the visible and near infrared region of the electromagnetic spectrum). Data was collected using the three sensors at multiple times throughout the season, Seven times from the 20th of June to August 17th in parcels with potatoes and five times from 8th of June to July 23rd in trials with winter wheat. The collected data were later used in creating a mosaic, from which values of reflectance was extract-ed and compared to traditional (manual) methods of estimating the severity of diseases. This was carried out throughout the season. The ambition of the present thesis was to test whether it is possible to use Unmanned Aerial Vehicle (UAV)-borne sensors to detect diseases in fields with potatoes and winter wheat. The evaluated diseases were potato late blight (Phytophtora infestans) and septoria leaf blotch (Septoria tritici). In winter wheat we were not able to find any correlation neither between single bands of reflectance nor vegetation indices (GRVI) and the amount of S.tritici in the crop (p>0.05). However, the GRVI-index was found suitable to evaluate the amount of green leaf area (p= 0.05) in the canopy. The season in which this study was carried out (2016) lacked in rain during June and July which might have contributed to the unusually low amount of fungal diseases recorded. The present thesis concludes that it is possible to detect areas with pos-sible infections due to changes in values of reflectance using multispectral sensors and its correlation to infections. It is possible to use it, together with manual field observations, as decision support for application of fungicides. However it is not certain the disease is detected early enough not to spread further into the field.FĂ€lt med potatis (Solanum tuberosum L.) och höstvete (Triticum aestivum L.) i vilka det pĂ„gick försök med fungicider undersöktes med tvĂ„ kameror (RGB-sensorer som registrerar ljus i det röda (R), gröna (G) och blĂ„ (B) vĂ„glĂ€ngdsomrĂ„-det) och en multispektral sensor (som registrerar ljus i fem smala band i det syn-liga och nĂ€ra infraröda vĂ„glĂ€ngdsomrĂ„det). Bildmaterial samlades in vid sju till-fĂ€llen mellan 20 juni och 17 augusti för potatisen och fem tillfĂ€llen mellan 8 juni och 23 juli för höstvetet. Mosaiker bildades av de bilder som tagits, ur vilka reflek-tansvĂ€rden sedan extraherades för att jĂ€mföras med manuellt utförda graderingar av angreppsgraden i bestĂ„ndet. Syftet var att se om sensortekniken var kapabel att upptĂ€cka sjukdomar i ett tidigt stadium och fungera som underlag för beslut om vĂ€xtskyddsbehandlingar alternativt anvĂ€ndas för dokumentation och gradering av angrepp i fĂ€ltförsök. I höstvete (som enbart undersöktes med RGB-sensor) kunde ingen statistiskt signifikant korrelation mellan förekomsten av svartpricksjuka (Septoria tritici) och reflektansvĂ€rden för enskilda band eller Green-Red-Vegetation Index (GRVI) ses (d.v.s. p >0.05) men tekniken visade sig istĂ€llet fun-gera för att bedöma bestĂ„ndets grönhet (p = 0,05), vilket ocksĂ„ var en bestĂ„nds-egenskap som graderades för hand. Året för undersökningarna (2016) fanns det en ovanligt lĂ„g förekomst av svampsjukdomar i fĂ€lt. Arbetet visar att det Ă€r fullt möj-ligt att utföra en datainsamling över fĂ€lt som baserat pĂ„ reflektansavvikelser kan detektera möjliga angrepp av bladmögel och efter manuell fĂ€ltkontroll styra fungi-cidbehandling. Det Ă€r dock tveksamt om vi ser resultaten i tid för att hindra en fortsatt spridning av bladmögel i bestĂ„ndet

    Computer Aided Learning for Students in Infectious Diseases

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    There is a perceived need to introduce computer-based learning into medical educational institutions, which still are using traditional teaching tools to a large extent. The overall goal of this project is to improve learning and teaching in the subject of infectious diseases with the aid of computer based learning, to make the students more active and better prepared for the first years of practice. We want both to maintain our present high teaching standards - in a tightening economic situation with reduced teaching resources - and at the same time develop our problem-oriented approach with active student participation. A central theme in undergraduate medical education is to identify and solve clinical problems through demonstrations and discussions of patient cases. It is often difficult to find an adequate number of patients with representative and important diseases. By using computer simulations of patient cases we can increase problem-oriented learning and stimulate student activity. For this purpose a new software system to simulate patient cases - Infaktiv - is being developed at the Department of Infectious Diseases in Uppsala, in collaboration with the hospital computer education centre, and with the support of the Council for the renewal of Undergraduate Education. It is intended for medical students attending infectious disease courses, and will be evaluated in regular teaching during 96/97. We also propose to activate student curiosity and stimulate to a global view of infectious diseases by utilizing Internet resources and our own hypertext material. We hope that with the aid of Internet learning each student can pursue his or her individual interests better, without compromising the basic and essential knowledge. A student Home page, consisting of the curriculum, questionnaires for answering clinical questions, forms for sending in criticism, directories of Internet resources, etc. will be constructed. We believe that our proposal represents an educational development that is inevitable, and already being implemented in several countries. We are convinced it will have a positive effect on student performance in solving clinical problems, and thus will have a long-term beneficial effect on our speciality. Establishing a network of colleagues in our field to promote the use of computers and Internet resources may also stimulate new ideas and lead to further initiatives in this area

    Effects of water content in the base of seedbeds for the emergence of sugar beet seedlings

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    To sow at optimal moisture content in the seedbed is crucial for good germination and emergence. In reality this is very complex and a farmer needs to take multiple parameters into consideration, such as the upcoming weather, the soil’s sensitivity to compaction and variations within the field. The current size-rationalization in Swedish farming where fewer farmers cover larger areas is not favourable for de-termining the right place on the right time in order to accomplish sowing for an optimal crop emergence. This bachelor’s thesis will cover a brief literature review followed by an experi-ment in the laboratory where sugar beet seeds were sown in seedbeds prepared with different water contents in the bottom layer, to give a hint at what moisture content we get the greatest crop emergence. When the experiment was carried out indoors in two trials, little or no emergence was observed from the sown sugar beet seeds. When the seedbeds were placed outside during the third trial the seedbeds with 9 and 12 percent plant available water showed better emergence, but due to a heavy rainfall which might have struck the seedbeds it is not certain if the results are reliable. Previous research from outdoor experiments has shown that the preferred moisture content in the seedbeds basal layer should be between 8 and 12 percent plant available water.För att lyckas med en optimal plantetablering frĂ„n det utsĂ€de som anvĂ€nds i lant-bruket Ă€r det av stor vikt att ha kunskap om vilken vattenhalt som ger den bĂ€sta förutsĂ€ttningen för uppkomst. Det kan i verkligheten vara svĂ„rt att lyckas sĂ„ vid optimala vattenhalter av flera orsaker, sĂ„ som vĂ€derlek, packningskĂ€nslighet, vari-ationer inom fĂ€ltet och inte minst den pĂ„gĂ„ende storleksrationaliseringen i det svenska lantbruket gör det svĂ„rt att vara pĂ„ rĂ€tt plats vid rĂ€tt tid. Detta kandidatarbete hade till syfte att genomföra en kort litteraturstudie och i möj-lig mĂ„n kunna koppla befintliga kunskaper till sockerbetsodlingen. Med ett labora-torieförsök testas fyra olika vattenhalter i sĂ„botten för att se vid vilken av dessa som uppkomsten Ă€r störst. MĂ„let Ă€r att nĂ„ resultat som ska kunna hjĂ€lpa odlare genom att ge en fingervisning om vilken vattenhalt som Ă€r den optimala för sĂ„dd, om man kan bortse frĂ„n andra faktorer som spelar in. Flera vattenhalter testades inomhus i tvĂ„ försök utan att resultera i nĂ„gon uppkomst av sockerbetor. I ett försök utomhus var uppkomsten bĂ€ttre, frĂ€mst i de högre vat-tenhalterna (9 och 12 procent vĂ€xttillgĂ€ngligt vatten) men pĂ„ grund av ett regn och risk för att vatten tagit sig in i vissa cylinderprover Ă€r det svĂ„rt att sĂ€ga om resulta-ten Ă€r pĂ„litliga. Tidigare forskning har i praktiska försök visat att den optimala vattenhalten i sĂ„bĂ€dden bör ligga mellan 8 och 12 procent vĂ€xttillgĂ€ngligt vatten

    Understanding the role of health information in patients' experiences: secondary analysis of qualitative narrative interviews with people diagnosed with cancer in Germany

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    Objective To analyse the role and meaning of health information in individuals' experiences with either breast, colorectal or prostate cancer in order to better understand unmet information needs of people with a cancer diagnosis. Design This is a secondary analysis of data from a qualitative interview study including narrative interviews and maximum variation sampling. A thematic analysis was conducted, followed by an in-depth analysis based on the principles of grounded theory. Setting Interviewees were sought across Germany through self-help organisations, primary care clinics, rehabilitation facilities, physicians and other healthcare professionals to develop cancer modules for the website kr ankheitserfahrungen.de (illness experiences.de). Participants Women with a diagnosis of breast cancer, individuals with a diagnosis of colorectal cancer and men with a diagnosis of prostate cancer. Results The meaning and role of information in the illness experiences were clearly associated with gaining control in a seemingly uncontrollable situation in which others people, the disease take over. Four categories characterise the ways in which information helped interviewees to regain a sense of control following a diagnosis of cancer: 'becoming confident in one's treatment decision', 'taking responsibility for one's situation', 'understanding the consequences of the disease and treatment for one's life', and 'dealing with fear'. There was, however, always a fine line between information seeking and becoming overwhelmed by information. Conclusions Information needs to be understood as a management tool for handling the disease and its (potential) consequences. Patients' unmet needs for information might not be easily solved by a simple increase in the amount of information because emotional support and respect for patient autonomy might also play a role. The evaluation of one's own information behaviour and the information received is closely linked to how the illness unfolds. This makes it challenging to document unmet information needs and satisfaction with information independent of an individual's illness trajectory over time

    HD 69686: A Mysterious High Velocity B Star

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    We report on the discovery of a high velocity B star, HD 69686. We estimate its space velocity, distance, surface temperature, gravity, and age. With these data, we are able to reconstruct the trajectory of the star and to trace it back to its birthplace. We use evolutionary tracks for single stars to estimate that HD 69686 was born 73 Myr ago in the outer part of our Galaxy (r∌12r \sim 12 kpc) at a position well below the Galactic plane (z∌−1.8z \sim -1.8 kpc), a very unusual birthplace for a B star. Along the star's projected path in the sky, we also find about 12 other stars having similar proper motions, and their photometry data suggest that they are located at the same distance as HD 69686 and probably have the same age. We speculate on the origin of this group by star formation in a high velocity cloud or as a Galactic merger fragment.Comment: 28 pages, 6 figures, accepted for publication in Ap

    Chirale Lactole, IV. SelektivitÀten bei Acetalisierungsreaktionen enantiomerenreiner Lactole am Beispiel von Octahydro-8,9,9-trimethyl-5,8-methano-2H-1-benzopyran-2-ol

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    Eine Synthese fĂŒr das Lactol 1 wird beschrieben und seine Eignung als Reagens zur Racemattrennung an einigen Beispielen gezeigt. Aufgrund einer Röntgenstruktur und konformationsanalytischer Überlegungen wird eine allgemeine Regel erarbeitet, nach welcher die Absolutkonfiguration acyclischer Alkyl-aryl-carbinole aus dem Verlauf der Acetalisierungsreaktion eines enantiomerenreinen Lactols mit dem racemischen Alkohol vorhergesagt werden kann

    Genome dynamics of Bartonella grahamii in micro-populations of woodland rodents

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    <p>Abstract</p> <p>Background</p> <p>Rodents represent a high-risk reservoir for the emergence of new human pathogens. The recent completion of the 2.3 Mb genome of <it>Bartonella grahamii</it>, one of the most prevalent blood-borne bacteria in wild rodents, revealed a higher abundance of genes for host-cell interaction systems than in the genomes of closely related human pathogens. The sequence variability within the global <it>B. grahamii </it>population was recently investigated by multi locus sequence typing, but no study on the variability of putative host-cell interaction systems has been performed.</p> <p>Results</p> <p>To study the population dynamics of <it>B. grahamii</it>, we analyzed the genomic diversity on a whole-genome scale of 27 <it>B. grahamii </it>strains isolated from four different species of wild rodents in three geographic locations separated by less than 30 km. Even using highly variable spacer regions, only 3 sequence types were identified. This low sequence diversity contrasted with a high variability in genome content. Microarray comparative genome hybridizations identified genes for outer surface proteins, including a repeated region containing the <it>fha </it>gene for filamentous hemaggluttinin and a plasmid that encodes a type IV secretion system, as the most variable. The estimated generation times in liquid culture medium for a subset of strains ranged from 5 to 22 hours, but did not correlate with sequence type or presence/absence patterns of the <it>fha </it>gene or the plasmid.</p> <p>Conclusion</p> <p>Our study has revealed a geographic microstructure of <it>B. grahamii </it>in wild rodents. Despite near-identity in nucleotide sequence, major differences were observed in gene presence/absence patterns that did not segregate with host species. This suggests that genetically similar strains can infect a range of different hosts.</p

    ACOOR Rapport 2: Översikt av tekniker och metoder

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    I arbetet med att modellera ett produktionsplaneringsproblem i jÀrnvÀgsindustrin har vi identifierat ett antal metoder och tekniker som vi hÀvdar Àr anvÀndbara Àven utanför jÀrnvÀgsdomÀnen. I denna rapport presenterar vi kort problemstÀllningarna i jÀrnvÀgsdomÀnen, presenterar de viktigaste av de tekniker vi identifierat, anvÀnt och utvecklat samt indikerar en del andra problemdomÀner för vilka vi bedömer att dessa tekniker skulle kunna anvÀndas
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