2,350 research outputs found
Magnetism in tetragonal manganese-rich Heusler compounds
A comprehensive study of the total energy of manganese-rich Heusler compounds
using density functional theory is presented. Starting from a large set of
cubic parent systems, the response to tetragonal distortions is studied in
detail. We single out the systems that remain cubic from those that most likely
become tetragonal. The driving force of the tetragonal distortion and its
effect on the magnetic properties, especially where they deviate from the
Slater--Pauling rule, as well as the trends in the Curie temperatures, are
highlighted. By means of partial densities of states, the electronic structural
changes reveal the microscopic origin of the observed trends. We focus our
attention on the magnetocrystalline anisotropy and find astonishingly high
values for tetragonal Heusler compounds containing heavy transition metals
accompanied by low magnetic moments, which indicates that these materials are
promising candidates for spin-transfer torque magnetization-switching
applications
A Novel Concept for Phase Error Correction in Superconductive Undulators: Theory and Experimental Verification
Undulators are the most advanced sources for the generation of synchrotron radiation in present storage rings. The photons generated by a single electron add up coherently along the electron trajectory. Small magnetic errors can cause unwanted destructive interferences. In this thesis a novel passive shimming method for superconductive undulators based on superconductive closed loops is presented. It is shown that the system can significantly reduce the effect of the field errors
Reorganizacija lokalne samouprave: između teritorijalnog povećanja jedinica i suradnje na dva stupnja
Territorial reorganisation of local governments can rely on voluntary or imposed mergers of general-purpose local units or on creating functionally oriented intermunicipal bodies. A detailed institutional analysis of the German and the French local self-governments has been conducted. In certain German Länder (Nordrhein-Westfalen, Hessen), consolidated local authorities were created during 1960s and 1970s. Others have chosen softer reform strategies, retaining small municipalities and introducing intermunicipal bodies. Recent reforms in East Länder are directed at enlarging local units by way of mergers. France faced an unsuccessful attempt to merge a large number of small local units in the beginning of 1970s. Intermunicipal bodies have traditionally been in the focus of institutional development. On the basis of 1999 legislation, there were substantial changes regarding intermunicipal bodies – communauté is a new kind of intermunicipal body with taxation power and additional functions. Legislation
of 2010 has provided for moving France (2014) towards territorial,
political and functional reform of its intermunicipal space by providing for the direct election of the councils of the communautés, by promoting metropoles as well as communes nouvelles. Other comparative examples, except Germany and France, are also analysed. Nordic model of consolidation by mergers has been practised, in different stages of their institutional development, in the U.K., Sweden, Poland, Bulgaria, Lithuania, Denmark, and more recently in Greece. Fragmentation, small units and intermunicipal cooperation are characteristics of the Czech Republic, Slovakia, and Hungary. Special attention is given to Turkish case, which develops in line with North European model based on merging small municipalities.Reorganizacija lokalnih samouprava može se osloniti na dobrovoljno ili nametnuto spajanje lokalnih jedinica opće namjene ili na stvaranje funkcionalno orijentiranih međuopćinskih tijela. Detaljno su analizirane njemačka i francuska lokalna samouprava. U nekim njemačkim zemljama (Sjeverna Rajna i Westfalija te Hessen) došlo je do okrupnjavanja lokalnih jedinica tijekom 1960-ih i 1970-ih, dok su druge njemačke zemlje odabrale umjerenije reformske strategije,
zadržavajući male lokalne jedinice i formirajući tijela za njihovu suradnju. Novije reforme u zemljama njemačkog istoka usmjerene su na stvaranje većih lokalnih jedinica spajanjem manjih. U Francuskoj je početkom 1970-ih došlo do neuspješnog pokušaja okrupnjavanja većeg broja malih lokalnih jedinica. Temeljem Zakona iz 1999. došlo je do značajnih promjena u pogledu tijela međuopćinske suradnje, jer je uvedena nova vrsta takvih tijela, communauté, s ovlastima oporezivanja i dodatnim javnim poslovima. Zakonodavstvo iz 2010.
omogućava da se teritorijalnom, političkom i funkcionalnom reformom od 2014. ojačaju oblici međuopćinske suradnje, jer određuje provedbu neposrednih izbora vijeća u toj novoj vrsti tijela (communautés), kao i snaženje metropoles i communes nouvelles. Osim njemačkog i francuskog analizirani su i drugi europski primjeri. Nordijski model okrupnjavanja spajanjem manjih lokalnih jedinica primijenjen je u različitim fazama njihovog institucionalnog razvoja
u Ujedinjenom Kraljevstvu, Švedskoj, Poljskoj, Bugarskoj, Litvi, Danskoj i u novije vrijeme Grčkoj. Fragmentacija, male lokalne jedinice i međuopćinska suradnja su karakteristične za Češku, Slovačku i Mađarsku. Posebna je pažnja posvećena razvoju lokalne samouprave u Turskoj, koja slijedi sjevernoeuropski model utemeljen na spajanju malih lokalnih jedinica
Phosphorus bioavailability of fertilizers recycled from sewage sludge and their suitability for organic crop production
Phosphorus (P) nutrition of plants is a key production factor in agriculture. In an approach to recycle P from urban areas back to agriculture, technologies have been developed to produce mineral P fertilizers out of municipal sewage sludge. In this study, different P fertilizers recycled from sewage sludge have been investigated in pot and field experiments for their bioavailability to maize and several plant species of a crop rotation. It was also investigated, if bioavailability of recycled P fertilizers can be enhanced either by a soil inoculation with different bacteria strains that are efficient in P solubilizing, or by a cultivation of red clover in the crop rotation. As there is a lack of bioavailable P fertilizers in organic cropping systems, P fertilizers recycled from sewage sludge were evaluated for their suitability to be used in organic crop production.
It has been shown that most of the investigated fertilizers recycled from sewage sludge have a higher P bioavailability than Phosphate Rock (PR). Fertilizer efficacy seems very dependent from specific production conditions which are decisive for the final product. Among the tested fertilizers, struvite (MgNH4PO4 . 6 H2O) was most efficient in increasing plant P offtake of maize (+ 27.5% in the field, and more than sixfold in a pot experiment, compared to the unfertilized control). Struvite and calcined sewage sludge ash (SSA) are efficient fertilizers at both acidic and neutral soil pH. Other fertilizers (e.g. untreated incineration ashes) have low solubility at soil with pH > 6, and thus, might be used on acidic soil only, or as raw material for fertilizer production. In the field experiment, the overall response to P fertilizer input was low, which probably can be attributed to a sufficient inherent P supply on the used site. An immobilization of fertilizer P over time could be shown in all experiments. Thus, recycled P fertilizers should be applied to responsive crops in the rotation. An improved P supply of maize could be shown when grown after red clover in the crop rotation. This might be attributed to a combination of different factors, such as a solubilization of sparingly soluble P forms in recycled fertilizers, following a drop in soil pH due to biological N2 fixation of clover. A recycling of P to maize via decomposed clover roots might in addition have contributed to an increased P supply of the subsequent maize. Despite this promising effect, P mobilization by clover cultivation was not sufficient to cover the entire P demand of maize. Thus, additional fertilizer P inputs to maize might still be necessary to ensure optimal plant growth on P deficient soils. With one exception, an application of different bacteria strains generally did not affect P supply of the plants. Applied bacteria seem very dependent on the environmental conditions. It is conceivable, that especially in organic systems, a soil application with external bacteria does not enhance the beneficial effects of a high microbial abundance and activity which often is already present in organic cropping systems.
From an agronomic point of view, P fertilizers recycled from sewage sludge are better alternatives for organic crop production than PR. A recycling of nutrients generally fits well with basic organic principles. By introducing those fertilizers, the organic system could make a decisive contribution to the ongoing effort of closing the P cycle, and, once more, develop towards a farming system of the future.So wie alle anderen Lebewesen, sind auch Pflanzen auf das Element Phosphor (P) angewiesen. Es ist umstritten, wie lange die natürlichen Rohphosphat (PR) Reserven noch ausreichen, um den P-Bedarf der Landwirtschaft zu decken. Vor diesem Hintergrund haben sich verschiedene Technologien entwickelt um P-Düngemittel aus kommunalem Klärschlamm zu gewinnen. Angesichts des Mangels an pflanzenverfügbaren P-Düngemitteln im Ökologischen Landbau wurde evaluiert, ob diese Recycling-P Düngemittel aus agronomischer Sicht für die Ökologische Pflanzenproduktion infrage kommen. Dafür wurden in dieser Studie verschiedene Recycling-P Düngemittel in Gefäß- und Feldversuchen mit mehreren Pflanzen einer Fruchtfolge auf ihre Pflanzenverfügbarkeit hin untersucht. Darüber hinaus wurde untersucht, ob durch eine Beimpfung des Bodens mit verschiedenen Bakterienstämmen, oder den Anbau von Rotklee in der Fruchtfolge, die Pflanzenverfügbarkeit der Recycling-P Düngemittel erhöht werden kann.
Es konnte gezeigt werden, dass die meisten Recycling-P Düngemittel eine höhere Pflanzenverfügbarkeit aufweisen als PR. Offenbar wird die P-Düngewirkung dabei insbesondere von den jeweiligen Produktionsbedingungen bestimmt. Von allen untersuchten Recycling-P Düngemitteln hatte Struvit (MgNH4PO4 . 6 H2O) die höchste P-Düngewirkung. Im Vergleich zur ungedüngten Kontrolle erhöhte eine Düngung mit Struvit die P Aufnahme von Mais um 27.5% im Feldversuch und um mehr als das sechsfache im Gefäßversuch. Struvit und kalzinierte Klärschlammasche (KSA) sind effektive P Düngemittel, unabhängig von den jeweiligen Bodenbedingungen. Andere Düngemittel, wie etwa unbehandelte KSA, weisen bei einem pH der Bodenlösung von > 6.0 hingegen eine niedrige Pflanzenverfügbarkeit auf. Diese kommen daher nur für eine Nutzung auf sauren Böden, oder aber als Rohmaterial für die Düngemittelproduktion infrage. Die allgemein geringe Wirkung der P-Düngung im Feldversuch ist wahrscheinlich auf eine ausreichende P-Versorgung des Versuchsstandorts zurückzuführen. In allen Versuchen konnte mit der Zeit eine Immobilisierung von Dünger-P im Boden gezeigt werden. Recycling-P Düngemittel sollten daher innerhalb einer Fruchtfolge zu Kulturen mit hohem P-Bedarf gedüngt werden. Eine gesteigerte P-Versorgung von Mais konnte durch einen vorherigen Anbau von Rotklee in der Fruchtfolge erzielt werden. Die Absenkung des pH in der Bodenlösung infolge biologischer Stickstofffixierung hat vermutlich zu einer erhöhten Pflanzenverfügbarkeit schwerlöslicher P-Verbindungen aus Recycling-P Düngemitteln geführt. Darüber hinaus hat möglicherweise auch eine Freisetzung von P aus zersetzten Kleewurzeln zu einer verbesserten P-Versorgung des darauffolgenden Maises beigetragen. Die durch den Anbau von Klee mobilisierte P-Menge war jedoch nicht hoch genug um den gesamten P-Bedarf von Mais zu decken. Zu Mais sind daher vermutlich zusätzliche P-Düngegaben erforderlich. Eine P-Mobilisierung durch die Applikation verschiedener Bakterienstämme konnte in nur einem Fall erzielt werden. Möglicherweise bleibt der gewünschte Effekt einer P-Mobilisierung durch zusätzlich applizierte Bakterien gerade im Ökologischen Landbau aus, für den eine hohe mikrobielle Aktivität im Boden charakteristisch ist. Aus agronomischer Sicht sind Recycling-P Düngemittel aus Klärschlamm geeignetere Alternativen als PR für die ökologische Pflanzenproduktion. Ein Nährstoffrecycling wird von ökologischen Leitlinien grundsätzlich befürwortet. Mit der Aufnahme dieser neuartigen Düngemittel kann der Ökologische Landbau einen entscheidenden Beitrag zur Schließung des P Kreislaufes leisten und sich - einmal mehr - zu einem Bewirtschaftungssystem der Zukunft weiterentwickeln
Deep Learning for Detection and Segmentation in High-Content Microscopy Images
High-content microscopy led to many advances in biology and medicine. This fast emerging technology is transforming cell biology into a big data driven science. Computer vision methods are used to automate the analysis of microscopy image data. In recent years, deep learning became popular and had major success in computer vision. Most of the available methods are developed to process natural images. Compared to natural images, microscopy images pose domain specific challenges such as small training datasets, clustered objects, and class imbalance.
In this thesis, new deep learning methods for object detection and cell segmentation in microscopy images are introduced. For particle detection in fluorescence microscopy images, a deep learning method based on a domain-adapted Deconvolution Network is presented. In addition, a method for mitotic cell detection in heterogeneous histopathology images is proposed, which combines a deep residual network with Hough voting. The method is used for grading of whole-slide histology images of breast carcinoma. Moreover, a method for both particle detection and cell detection based on object centroids is introduced, which is trainable end-to-end. It comprises a novel Centroid Proposal Network, a layer for ensembling detection hypotheses over image scales and anchors, an anchor regularization scheme which favours prior anchors over regressed locations, and an improved algorithm for Non-Maximum Suppression. Furthermore, a novel loss function based on Normalized Mutual Information is proposed which can cope with strong class imbalance and is derived within a Bayesian framework.
For cell segmentation, a deep neural network with increased receptive field to capture rich semantic information is introduced. Moreover, a deep neural network which combines both paradigms of multi-scale feature aggregation of Convolutional Neural Networks and iterative refinement of Recurrent Neural Networks is proposed. To increase the robustness of the training and improve segmentation, a novel focal loss function is presented.
In addition, a framework for black-box hyperparameter optimization for biomedical image analysis pipelines is proposed. The framework has a modular architecture that separates hyperparameter sampling and hyperparameter optimization. A visualization of the loss function based on infimum projections is suggested to obtain further insights into the optimization problem. Also, a transfer learning approach is presented, which uses only one color channel for pre-training and performs fine-tuning on more color channels. Furthermore, an approach for unsupervised domain adaptation for histopathological slides is presented.
Finally, Galaxy Image Analysis is presented, a platform for web-based microscopy image analysis. Galaxy Image Analysis workflows for cell segmentation in cell cultures, particle detection in mice brain tissue, and MALDI/H&E image registration have been developed.
The proposed methods were applied to challenging synthetic as well as real microscopy image data from various microscopy modalities. It turned out that the proposed methods yield state-of-the-art or improved results. The methods were benchmarked in international image analysis challenges and used in various cooperation projects with biomedical researchers
Heusler 4.0: Tunable Materials
Heusler compounds are a large family of binary, ternary and quaternary
compounds that exhibit a wide range of properties of both fundamental and
potential technological interest. The extensive tunability of the Heusler
compounds through chemical substitutions and structural motifs makes the family
especially interesting. In this article we highlight recent major developments
in the field of Heusler compounds and put these in the historical context. The
evolution of the Heusler compounds can be described by four major periods of
research. In the latest period, Heusler 4.0 has led to the observation of a
variety of properties derived from topology that includes: topological metals
with Weyl and Dirac points; a variety of non-collinear spin textures including
the very recent observation of skyrmions at room temperature; and giant
anomalous Hall effects in antiferromagnetic Heuslers with triangular magnetic
structures. Here we give a comprehensive overview of these major achievements
and set research into Heusler materials within the context of recent emerging
trends in condensed matter physics
CYP3A-fenotype hos leddgiktpasienter i relasjon til inflammasjonsstatus og behandling med biologiske DMARDs
Bakgrunn: Enzymer tilhørende cytokrom P-450 3A (CYP3A)-subfamilien er de viktigste i metabolisme av legemidler. Systemisk inflammasjon er foreslått som en faktor til den store interindividuelle variabiliteten i CYP3A-fenotype, og 4β-hydroksykolesterol (4β-OH-K) er en aktuell biomarkør for denne variasjonen. Hensikten med dette masterprosjektet var å undersøke om CYP3A-fenotype, målt som serumkonsentrasjon av 4β-OH-K, i) endres etter oppstart med biologiske DMARDs (disease-modifying antirheumatic drugs/ sykdomsmodifiserende antirevmatiske legemidler, bDMARDs) hos leddgiktpasienter, og ii) skiller seg mellom leddgiktpasienter og personer uten kjent revmatisk sykdom. Sekundært skulle det også undersøkes i hvilken grad 4β-OH-K korrelerer med inflammasjonsstatus, målt som CRP og senkningsreaksjon (SR), før og etter oppstart med bDMARDs. Metode: Masterprosjektet tok utgangspunkt i registerstudien NOR-DMARD koordinert av Revmatologisk avdeling, Diakonhjemmet Sykehus. I alt 59 pasienter behandlet med bDMARDs i ca. 3 måneder mot revmatoid artritt (RA) og 52 levetiracetam-behandlede pasienter uten kjent revmatisk sykdom ble inkludert i prosjektet. Serumkonsentrasjon av 4β- OH-K ble bestemt ved bruk av en validert UPLC-APCI-MS/MS-metode ved Senter for Psykofarmakologi, Diakonhjemmet Sykehus. Nivåer av 4β-OH-K og inflammasjonsmarkører (CRP og SR), før og etter oppstart med bDMARDs, ble sammenlignet ved parrede, ikke- parametriske, tester («Wilcoxon»). En ikke-parametrisk, uparret test («Mann-Whitney») ble brukt for sammenligning av 4β-OH-K-konsentrasjoner mellom antatt friske og RA-pasienter, og Spearmans signed rank test ble benyttet i korrelasjonsanalysene mellom 4β-OH-K, CRP og SR. Resultater: Median CRP og SR var redusert, henholdsvis fra 6 til 2 mg/L (p=0.07) og fra 23 til 14 mm/h (p0.3), men etter 3 måneders bDMARD-behandling ble det observert signifikant korrelasjon (p<0.01, Spearman r -0.40 (CRP) og -0.34 (SR)). VI Konklusjon: Denne studien indikerer at CYP3A-fenotype er redusert med ca. 20-30 % i RA- pasienter sammenlignet med pasienter uten inflammatorisk sykdom. Behandling med bDMARDs forbedrer ikke CYP3A-fenotype i løpet av 3 måneder, men CYP3A-fenotype er negativt korrelert med nivå av inflammasjonsmarkører etter oppstart med bDMARDs
Assessment of Alternative Phosphorus Fertilizers for Organic Farming: Sewage Precipitation Products
The application of sewage sludge to agricultural land is currently prohibited in organic farming due to the risk of soil contamination from harmful compounds. Incineration or disposal to landfill of sludge is costly, leads to increased greenhouse gas emissions, and neglects the possibility of nutrient recovery. There are various technologies to recover P by crystallization or precipitation from waste water and sewage sludge. Depending on the input material, nutrient concentrations and concentration of contaminants can vary widely. Regarding the content of potentially toxic elements, the trade-offs between (potentially) toxic element concentrations and potential benefits may be more favorable for treated sewage products than for several natural phosphate rocks or even animal manures or bio waste compost. This fact sheet describes the most important aspects to assess the suitability of sewage sludge precipitation products for use in organic farming
- …